Woodlands Primary School Mathematics Calculation Policy Woodlands Primary School Guidance for the Calculation Policy Woodlands Primary School: Calculation policy Policy reflects: concrete (do it) abstract (see it!) visual (remember it!) communication (record it!) At Woodlands, we believe that an ability to calculate mentally lies at the heart of calculation. The foundations of good number sense, mental calculation and the recall of number facts need to be established thoroughly before formal written methods are introduced. National Curriculum Core Aims: 1. Developing Fluency Regular opportunities will be provided so that children become fluent in their ability to apply their knowledge with increasing accuracy and speed to a range of problems. 2. Reason Mathematically All children will have regular opportunities to follow lines of enquiry, conjecture relationships and make generalisations. Use of specific mathematical vocabulary will be promoted and modelled by adults regularly so that children become skilled in ‘developing an argument, justification or proof using mathematical language.’ 3. Problem Solving Throughout all stages of the policy, we aim to give pupils the opportunity to acquire a range of strategies which can be applied to solve problems, particularly more complex problems where two or more steps are needed. Opportunities to solve different types of problems will be provided regularly so that children are able to apply their mathematics with ‘increasing sophistication.’ Through regular exposure to problem solving, children will become skilled at breaking complex problems down into simpler steps; they will tackle problem solving with a high level of independence, making decisions and showing resilience as they persevere in finding a solution. Progression from mental to written methods: Our aim is for all children to have a reliable and efficient method for calculating in all four operations. The four operations will be known as addition, subtraction, multiplication and division from Foundation stage to Year 6. Mental strategies will include the teaching of informal recording and personal jottings. November 2016 We will use models and images to support the development of mathematical concepts. Where particular resources need to be used, they have been identified in the policy. We will use concrete models, abstract images and visualising to secure understanding and build memory. The calculation policy tracks the mental skills required for each written method and these should be taught progressively. The policy will also support the diagnosis of errors and can be used to make judgements about the stage of development. Specific language (blue text) which can be used to support and explain calculation has been notated with a blue speech bubble. It is expected that all staff and pupils will use this language. Use of the Calculator The calculator will continue to be used as a teaching and learning tool across school. It should not replace written calculation methods but may be used in lessons when the focus is on other skills e.g. problem solving. Decision Making Children should have sufficient understanding of the calculation in front of them so that they can decide which method to use – mental, mental with jottings, informal written method, formal written method or a combination of these methods. Our aim is for children to apply these accordingly, with confidence. Editing Children should be actively encouraged to check and edit their work. When work is edited, this should be completed using red edit pen (as stated in the school presentation policy). Cross curricular links Cross curricular links are planned for to ensure children experience mathematics in a wider range of contexts. As a school, we believe it is vital that children gain an understanding of how mathematics is linked to real life contexts. Implementation and review Staff will receive the updated policy – November 2016. Staff will use the policy to plan for progression in calculation. Implementation of the policy will be reviewed regularly by the Mathematics subject leader. Bar Model Calculation Appendix to be used alongside calculation policy – November 2016 November 2016 Woodlands Primary School: Progression in Number Sense Concrete: Abstract: Visual Number sense: nrich.maths.org :: Mathematics Enrichment :: Number Sense Series: Developing Early Number Sense nrich.maths.org :: Mathematics Enrichment :: Number Sense Series: A Sense of 'ten' and Place Value Learning to count with understanding is a crucial number skill, but other skills, such as perceiving subgroups, need to develop alongside counting to provide a firm foundation for number sense. To begin with, early number activities are best done with moveable objects such as counters, blocks and small toys. Models and images By simply presenting objects (such as stamps on a flashcard) in various arrangements, different mental strategies can be prompted. After the essential experiences of practical apparatus more static materials such as 'dot cards' become very useful. Abstract – Counting ITP Which are instantly recognised and which are counted? If mental strategies such as these are to be encouraged (and just counting discouraged) then an element of speed is necessary. Seeing the objects for only a few seconds challenges the mind to find strategies other than counting. It is also important to have children reflect on and share their strategies. Combining – Abstract – Counting ITP Concrete models Random arrangements that can be counted. Random arrangements that can be ‘subitised’ e.g. 5 beads and 2 beads. Linear arrangements, such as a bead string Recognising the 4 and then the 3, combining this to make 7.Counting on from 4 rather than counting all 7 November 2016 Learning focus Distinguish between quantities; recognise when a group of objects is more than one Concrete Abstract Use published pictures and photographs of every day objects recognisable to the children (both inside and outside of the classroom) that show only one object and more than one. For example: fruit, animals, cars Provide opportunities through play for children to identify sets containing ‘only one’ object and those containing more than one. One bear all alone You will need: small plastic bears or other objects, opaque plastic cups or bowls Place three or four bowls upside down on a table. Place a single bear under one of the bowls and different quantities of bears under the others. Invite children to help you. Tell the children that you are looking for the lonely bear, the one all on its own. Ask the children to take turns to turn over a cup or dish, encouraging them to describe what they have found. Use prompts and questions such as: Tell us what you have found. Have you found one bear or more than one? Encourage children to take the bears that they find and to place them in a line in front of them. Prompt children to compare the number of bears that they have, by asking questions such as: Do you think that Max or Evie found more bears? How could we check? Invite the children to play again by placing their bears back under a cup. The child who found the lonely bear could mix the cups around before you play again. Taking ideas further: Provide appealing objects and containers for November 2016 children to use in their play. Ensure that you provide some containers with lids to encourage children to guess which or how many objects may be inside. Recognise groups with one, two or three objects Subitising with objects. For example, provide equipment that has to be counted e.g. matches, multilink and counters. Children then count out 1, 2 and 3 from each set of objects. Any activity that uses images of one, two or three objects. For example: One, two or three? You will need: three hoops, number cards 1, 2 and 3, some photographs of objects normally found individually or in pairs, images of groups of three objects, a camera Place a couple of cards or objects into each hoop so that one hoop contains individual objects (such as a photograph of a nose, a bin), a second contains objects normally found in twos (such as a photo of two eyes, a pair of socks) and the third contains images of objects in groups of three (such as wheels on a tricycle, legs on a three-legged stool, triplets). Invite children to help you to add to the display. Encourage them to look at the objects in each hoop so far and to suggest how you have sorted the objects. If no one suggests that you have sorted them by number, show children the number cards 1, 2 and 3 and say that these cards could be used to label the hoops. Which number goes with which hoop? Why? Encourage children to go for a walk (in pairs or a small group), inside and outside, to find other items that could be added to the display. Explain that if children cannot bring the actual objects, they can make a drawing or use the camera to take a photograph. Walk around with children, observing if they can instantly identify whether sets contain one, two or three items. Taking ideas further: Play ‘Odd one out’, asking children to close their eyes while you move an object from one of the hoops to another. Can the children identify which object you have moved? November 2016 Match and compare the number of objects in two sets, recognising when the set contains the same number of objects. Provide opportunities for children to compare two sets of objects through malleable play. (page 9 of enabling environments) Abstract – Counting ITP Use counting ITP to compare 2 sets of objects. Find five You will need: hoops or plates, five each of three interesting objects (to hide) Show children objects that you have chosen to hide and explain that there are five of each of these hidden around the building, inside and outside. Invite children to go on a hunt to find the hidden objects. Suggest that as soon as they find an object, they bring it back and place it on the table or floor. Encourage children to hunt in pairs so that they can discuss their ideas. Observe and listen to children as they hunt. Discuss the hunt with children, for example: I can see that you have found two key-rings. Have you found anything else? After a while, call children together by the pile of objects to look at what has been found so far. Lead a discussion about what has been found. Use prompts such as: • Could we organise the objects to see clearly what we have found so far? (Use hoops or plates to sort the objects.) • How many stars have we found? • Can you show me this number on your fingers? • Have we found all of them yet? • Which object have we found least of (or most of) so far? How do you know? Encourage children to hunt for the remaining objects until they are all found. Taking ideas further: Change the number of each object hidden. Ask November 2016 children if they can work out how many of each object they still need to find. Instantly recognise without counting familiar patterns of up to six objects. Use apparatus such as dice, playing cards and dominoes which have a structured pattern for instantly recognising a number and get children to replicate using counters. Use pelmanism memory game to match familiar patterns of up to six objects. Make dominoes You will need: sticky dots, rectangular cards in different colours, cut into domino-shaped cards with a central line Invite children to make their own sets of dominoes with up to four dots in total. Encourage children to explain what dominoes look like. Give children different-coloured card. Explain that you are going to start by making all of the different dominoes that you can that use only one dot altogether. Ask everyone to have a go at making a domino that has only one dot.Make a domino November 2016 yourself so that you can model the use of mathematical language, for example:I have one dot. I am going to place it on this side of my domino. Compare children’s examples.Show that it doesn’t matter which side you stick the dot by turning the dominoes around. Next make dominoes that have two dots. Encourage children to discuss what they are doing and to compare their dominoes. Use prompts such as: • You have taken two sticky dots. Where are you going to stick them now? • Paul and Sam’s dominoes look different. Why? Do they both have two dots altogether? Encourage children to make sure that they have all possible ways of using the dots each time. Where necessary, use questions such as: Sam, you have made a two-dot domino with both dots on the same half of the domino. How could you put two dots onto this domino so that they are not on the same half? Continue until children have made all possibilities up to a total of four dots. Encourage them to look at the sets they have created. Ask questions such as: • Can you find all of the dominoes with three dots on one half? • Who can describe the way that the dots are organised on this domino? • How many dots altogether are there on this domino? Taking ideas further: Children could play games with their sets of dominoes. Instantly recognise, without counting, organised and random arrangements of small numbers of objects Practical Subitising with numbers greater than 6, but within the counting experience of the child. Bead strings, coins, counters, straws, matchsticks can all be used to set up arrangements using the familiar patterns previously explored (using dice, dominoes and playing cards), linear arrangements (beads) as well as random arrangements. Abstract – Counting ITP Opportunities for children to recognise random and organised arrangements. November 2016 Going dotty You will need: 3 × 3 squared paper (to use to make dot patterns for numbers), sticky dots to fit into the squares, a dotty dice Invite children to help you make cards to play a game. Ask children to show you the face of the dice that has six dots on it. Encourage children to consider the pattern of the dots. Use prompts such as: How did you recognise so quickly that this face has six dots? What is special about the pattern? Respond to comments, reinforcing mathematical vocabulary, for example: Jamie said that the dots are in two lines. How many dots are in each line? The six dots are in two rows (pointing), with three dots in each: one, two, three... one, two, three. Ask each child to take a piece of squared paper and some sticky dots and make the same pattern of six dots. Encourage them to talk about what they are doing. Use prompts such as: How many dots have you stuck down so far? What are you going to do next? Show children a different arrangement of six dots and ask them how many dots they can see. Establish that there will be lots of ways to organise six dots onto squared paper. Ask each child to try to find a different arrangement. Work together in a similar way to produce different patterns of five, four and three dots and use them in a game. Place the patterns in the middle of the table, face down. Then children take turns to select two patterns. If they show the same number of dots then they keep the pair. Taking ideas further: Use the cards for similar matching games such as snap. Use the skills of subitising to combine two sets of objects with or without counting in the range of 1-10. Work with two sets of objects that children arrange into recognisable formations. Are children able to say how many there are altogether? Random to recognisable patterns for addition. November 2016 Combining boxes You will need: boxes containing different numbers of items (each labelled with the number of items inside), number cards to 20 or blank labels Pick two boxes and show them to the children. Ask what they think the number on each box tells them. Check by asking children to count the objects in each box. Explain: We are going to put the objects from these two boxes together. Abstract – Counting ITP We need to work out how many objects that will give us altogether. How could we do that? Encourage children to suggest different methods and try them. Include counting on methods, for example: There are eight objects in this box and three in the other. Let’s add the three objects into this box. Ask children to count aloud as each object is dropped in, giving the total number of objects in the box so far: We started with eight, that’s nine, ten, eleven. How many objects are there altogether? Write the total on a sticker. Ask children to work in pairs, to choose two boxes and combine the objects into one box, working out the total to record on the box. Observe how children go about this. Taking ideas further: Carry out similar subtraction activities, taking some items from one box to put into another and working out how many objects are left in the first box. November 2016 Addition Counting objects, partitioning and recombining sets using practical apparatus. Understand that the number gets bigger. Addition is commutative. Use number tracks to develop counting skills, forwards and backwards. Subtraction Know that the number gets smaller because objects have been removed from the set (unless you subtract zero). Stage A (R/Y1) Multiplication Jumping along number lines in jumps of 1,2,5 & 10. Counting on and back in steps of 1,2 and 10. Sharing objects equally, practical contexts. Repeated addition, practical demonstrations. Models and Images charts Pictorial recording. Practical models of subtraction Counting back on fingers, orally, number lines (Take-away). Find the mathematical difference (Counting on). Models and Images charts. Doubles and grouping. Grouping is a random arrangement of a quantity into equal groups. Grouping, in practical contexts. GROUPING ITP Arrays are a rectangular arrangement to show the equal groups. COUNTING ITP Pictorial recording of practical experiences. Teacher modelling of number sentences and addition as commutative. Division Use cross curricular links (PE) and purposeful objects such as sock and shoes/ animals in the ark to get into groups. Sharing models such sharing an apple or a Satsuma. How many cars can you make if you have 8 wheels? This is an array Grouping and sharing, practically. (NB If the answer is in the same units as the dividend, it is sharing. If the answer is in different units, it is grouping.) November 2016 Example: Dividend ÷ Divisor = Quotient £20 ÷ 4 = £5 (Sharing) £20 ÷ £4 = 5 (Grouping) Use of arrays to show that multiplication is commutative. Changing the order does not affect the answer. Peg boards are a useful model. NUMBER FACTS ITP Practical demonstrations of take away. Use the language of ‘lots of’, ‘groups of’ and ‘sets of’ for ‘x’. There were 9 balloons. Two popped. How many are left? Once numbers can be written, number sentences can be recorded. 9–2 =7 Modelling of commutative layout. November 2016 Bar Model To have experience of ‘=’ sign as last stage in calculation. GROUPING ITP ADDITION AND SUBTRACTION EXCEL Pictures to show 2 lots of 3 or 3 lots of 2. 10 – 6 =4 Find the mathematical difference where numbers are close together. “How many more do I add to 7 to get to 9?” DIFFERENCE ITP For Subtraction, reinforce the order of calculation. E.g BIGGEST NUMBER FIRST 9–7 =2 ______________ 7 8 9 Vertical number line to show the mathematical difference. 9 8 7 November 2016 Link to Diennes model e.g. 9 - 7= 2 Link to Beadstring model (for difference). Addition Subtraction Key skills of knowing number bonds to 10. Subtraction sentences and jumps along number lines. (backwards for take away – left and forwards for difference – right) along number lines. Develop knowledge of fact families, e.g. 2, 5, 7. EXCEL ADDITION AND SUBTRACTION TRIOS EXCEL ADDITION AND SUBTRACTION TRIOS Stage B (Y1/2) Multiplication Pictorial repeated addition. Grouping is a random arrangement of a quantity into equal groups. Arrays are a rectangular arrangement to show the equal groups. Division With practical equipment: Counting on and back in 2s, 5s and 10s and begin counting in 3s and 4s. Grouping as repeated addition along the number line. Introduce the ÷ symbol once repeated addition (grouping) is understood. November 2016 GROUPING ITP If I have got 4, how many groups of 2 have I got? Counting forwards and recording on a number line. All answers to be recorded in a number sentence following any informal recording. COUNTING ON AND BACK ITP 4+8 = Recording in number sentences and communication along number lines or with informal written methods. +2 +2 ______________________________ 0 2 4 Know that 6 can be thought of as 5 and 1. Counting in 2s, 5s and 10s and begin counting in 3s and 4s. Know that 8 is 5 and 3 therefore subtract 5 then 3. 7 Grouping and sharing, practically. (NB If the answer is in the same units as the dividend, it is sharing. If the answer is in different units, it is grouping.) Example: Dividend ÷ Divisor = Quotient £20 ÷ 4 = £5 (Sharing) £20 ÷ £4 15 – 8 =7 = Reordering – biggest number first. 8+4 Check with the inverse. _______________ __ 10 15 leading to = 5 (Grouping) Introduce the x symbol once repeated addition is Record sharing by using pictorial notation understood. There are 6 cakes and 2 children. How many cakes will they each get? One for you and one for you -3 -5 _______________________ 7 10 15 Children to show notation Find the mathematical difference by counting on along a number line. Share November 2016 leading to leading to 15 – 8 = 5 hops in 15.How big is each hop? Reinforce the role of the number sentence. 15 ÷ 5 =3 15 shared between 5 +2 +5 _________________________________ 8 10 15 Children to show notation Addition is the inverse of subtraction. Fact family. Children to show notation Use patterns to find answers to subtractions 10 + 4 = 5+5+5+5+5+5 5 5 6 6 = 30 × 6 = 30 multiplied by 6 groups of 5 hops of 5 There are 7 cakes and 2 children. How many cakes will they each get? = 20 + 4 = 20 – 4 = 10 – 4 =5 3+2 =5 5–3=2 5–2=3 2+3 Using shapes to represent a missing number. 1 group of 3 2 groups of 3 EXCEL PATTERNS OF CALCULATION Decision making 17 - = 12 Sam works out 17 – 5 = 12. How could he have done this? =3 ‘Left overs’ introduced. =6 Doubles and grouping recorded on number lines 2+2 = +2 +2 ________________________________ 0 2 4 Children to show notation There are 20 sweets in a bag. How many children can share them if they each have 5? +5 +5 +5 +5 _____________________________________ 0 5 10 15 20 November 2016 Adding more than two numbers Strategy to include looking for bonds that are useful eg bonds up to and including 10, doubles or adding 10 to a given number. 2+2+2 +2 = +2 +2 ___________________________________ 0 2 4 6 -5 -5 -5 -5 _____________________________________ 0 5 10 15 20 20 5 =4 Children to show notation Introduce the x symbol once repeated addition is “How many groups of 5 are there in 20?” understood. Children to show notation Compensation strategy 3x2 = 6 3 multiplied by 2 equals 6. 3 times 2 equals 6 3 lots of twos 5+9= 5 + 10 – 1 +10 ____________________-1___________ 5 14 15 Children to show notation Doubles then near doubles 5+6 = 5+5+1 7+8 = 11 = 8+8 -1 = 15 In the example above with 5 rows and 9 columns, when you select to count along the columns the given calculation is: 5 x 9 = 45 [the 5 is multiplied by 9]. Selecting to count along rows gives: 9 x 5 = 45 [the 9 is multiplied by 5]. November 2016 Decision making Using statements such as Ben did 14 + 9 = 23 How could he have done it? To know that the = sign means ‘the same as’ and can appear in a different place within a calculation; E.g. 14 = 8 + 6 Addition Emphasis on mental calculation Subtraction Place value, partitioning and recombining. Combining sets to make a total. Progression in use of informal recording including the number line. Answers to be recorded as part of a number sentence. Reordering strategy. COUNTING ON AND BACK ITP NUMBER LINE ITP Rearranging of numbers so that 36 can be seen as 30 and 6 or as 20 and 16. Stage C (Y2/3) Multiplication Division Using tables facts 2s, 10s, 5s, 3s and 4s. Understand division as repeated addition, grouping Be able to partition a 2 digit number. Table facts (see multiplication) MULTIPLICATION BOARD ITP Division facts corresponding to the 2, 10, 5, 3 and 4 times tables MULTIPLICATION TABLES ITP Partitioning of numbers into T and U then HTU. Know what each digit Doubles are same as x2 represents. Vocabulary of double, multiply, groups of, sets of, lots of etc. TU – TU HTU – TU Partitioning strategy for doubling Double 35 Use x and ÷ signs MULTIPLICATION AND DIVISION TRIOS SPREADSHEET Count a handful of beads by grouping them in fives. How many groups of 5 are there? How many are left? Can you write a division sentence to describe this? November 2016 24 + 30 x 2 58 5x2 How many lengths of 6 m can you cut from 48m of rope? Write the number fact that represents this. How did you work it out? Record using the correct division symbol adding in 10s and 1s Use of number lines to record repeated addition. Practical apparatus to support concept. add 20, bridge the 10 Practical contexts to be used so that the calculation is not in the abstract. Grouping add 20 and then 4 Record partitioned steps in number sentences underneath each other and add mentally. Use of inversion loops or the bar model (these provide a good visual representation of the inverse relationship). A lolly costs 21p. How much do 3 cost? _________________________ 0 2 4 6 8 24 + 58 20+50 =70 4+ 8= 12 24 + 58 =82 8÷2 =4 “How many groups of 2 are there in 8?” Introduce column addition without crossing the boundary 24 (20+4) +53 (50+3) 77 (70 + 7) _______________________________ 0 2 4 6 8 PLACE VALUE ITP Decision making The number of jumps tells you the number of groups. Children investigate statements and solve word problems using appropriate methods such as mental/ jottings/ numberline. DOUBLING AND HALVING SPREADSHEET November 2016 Check answers by repeating addition in different order or by an equivalent calculation. Compensation strategy 34 + 9 = +10 -1 ________________________ 34 43 44 Partitioning the second number strategy 76 – 43 = 76 – 40 = 36 36 – 3 = 33 73 – 46 = 73 – 40 = 33 33 – 6 = 27 Statements and word problems (mental/ jottings/ numberline) 16 2 = “How many groups of 2 are there in 16?” “I know that dividing by 2 is the same as halving.” Jump size depends on knowledge and confidence of child. (See D) 20 5 = Near doubles 13 + 14 = Double 14 = 28 28 – 1 = 27 or Double 13 = 26 26 + 1 = 27 PLACE VALUE DOTS EXCEL SPREADSHEET EXCEL MISSING SIGNS AND NUMBERS 55 – 27 4 jumps or moving away from Counting back (left) from the larger number in partitioned steps of the smaller number to reach the unknown. Partitioning the 27 into 20, 5 and 2. ← Adding zero leaves a number unchanged/ adding ten to a number keeps units digit constant. Decision making (mental, jottings, -2 -5 -20 _____________________________________ 28 30 35 55 55 – 27 + notation 2 double jumps because 5x2 =10 Decision making Children investigate statements and solve word problems using appropriate methods such as mental/ jottings/ numberline. = 28 November 2016 numberline) Statements and word problems. or or Find the difference (counting on to the right) 55 – 27 = 28 “How many more do I need to add to 27 to get to 55?” +3 +20 +5 ________________________________ 27 30 50 55 Subtract mentally pairs of multiples of 10 and 100, using known facts 60 – 20 = 700 – 300 40 because 6 – 2 = =4 400 Continue to use the vertical number line. November 2016 Use of apparatus (Diennes) to understand rearrangements, eg 72 as 60 and 12, not as part of calculations. BEADSTICKS ITP to be used with diennes to develop concept of exchange. PLACE VALUE ITP Decision making Statements and word problems. Addition Counting on in multiples of 100s, 10s or units using a number line. HTU + TU, HTU + HTU. Cross the 10s/100s boundary. Subtraction Stage D (Y3/4) Multiplication Division Counting backwards and forwards beyond zero, negative and positive numbers. Known table facts 2,3,4,5,6, 8 and 10. Know all for 2,3,4,5,6, 8 and 10. NUMBER DIALS ITP Know what each digit represents in a HTU number -5 is negative 5 and minus 5 MULTIPLICATION TABLES ITP November 2016 TU – TU, HTU – TU, HTU – HTU Lead on to decomposition method in expanded format. NUMBER BOARDS (all stages onwards for a range of numbers) Start with least significant digit 67 + 24 11 (7+4) + 80 (60+20) 91 Ensure understanding of number partitioning and exchange. Use of apparatus (Diennes) to understand rearrangements, eg 72 as 60 and 12, not as part of calculations. “7 add 4 equals 11 and 60 add 20 tens Know what each digit represents, partition a three digit number Commutative law (the principle that the order of two numbers in a multiplication calculation makes no difference, e.g. 5x7=7x5). MOVING DIGITS Consolidate arrays and repeated addition. Recalling facts. = 5x4= = 1 and 1 ten + 8 = 9 tens” 625 + 48 13 (5+8) 2 12 22 32 42 52 62 Least significant digit is always dealt with first to establish if the exchange is needed. Check for mental approach first before written method. “Can I do this in my head?” Use numbers that will generate remainders. ‘r’ notation for the remainder. 21 ÷ 5 = 4 r 1 4x5 70 60 50 40 30 20 10 equals 80. 1+ 0 Multiply by 10 / 100, understanding the shift in the digits 20 20. Use partitioning/re-arranging to find multiples of the divisor. Partitioning method 48 3 ‘What do I know about the divisor/3 x tables?’ “I know 3 x 10 Informal recording of partitioned numbers 6x3 30.” = = 16 18 10 x 3 = 30 = 75 = 50 5 x 5 = 25 10 x 5 27 x 3 = 30 18 10 6 48 3 15 x 5 = Decision making = 81 20 x 3 = 60 November 2016 60 (20 + 40) + 600 (600 + 0) 673 NUMBER BOARDS (all stages onwards for a range of numbers) 7x3 = 21 Reduction Strategy All language in the context of the place value and the mental addition of the totals to be done in any order. 625 + 48 673 Decision making. 783 – 356 300, 50 and 6 -6 -50 427 433 483 783 – 356 = 427 -300 783 Difference strategy Moving from left to right “ 20 multiplied by 3 equals 60 and 7 multiplied by 3 equals 21. 60 add 21 equals 81.” 23 x 8 = 20 x 8 =160 3 x 8 = 24 “How many more do I need to get from 356 to 783?” Leading to Both strategies need to record the answer in a number sentence 783 -356 23 x 8 24 (8 x3) 160 (8 x20) 184 Decision making = 427 November 2016 “783 to subtract 356 equals 427” 89 = 80 - 24 = 20 9 4 60 5 = 65 “9 subtract 4 equals 5 and 80 subtract 20 equals 60. 60 and 5 make 65” Vertical number line 24 +6 30 +50 80 +9 89 “Add 6 to 24 to make 30. Add 50 to 30 to make 80. Add 9 to 80 to make 89. So 6 add 50 add 9 equals 65.” 81 = 80 1 - 57 50 7 = __ ______________ “ 1 subtract 7 is tricky so I will rearrange 81 into 70 and 11. 11 subtract 7 equals 4 and 70 subtract 50 equals 20. 20 and 4 make 24.” 81 = 70 - 57 50 ___ 20 11 7 4 = 24 November 2016 “I’m going to exchange a _____ for a _____.” BEADSTICKS ITP Decision making Addition Continue with HTU + HTU, then extend to ThHTU + ThHTU. Approximate using the most significant digit, rounding skills. Check using the inverse. Refer to the carried digit as a ten or a hundred. Subtraction Stage E (Y4/5) Multiplication HTU – TU, then HTU – HTU Know table facts up to 12 x 12. (ThHTU – ThHTU) Approximate first. Know division facts corresponding to tables up to 12 x 12 Approximate first using multiplication facts. (THHTU – HTU) Extend to simple decimals with or without exchange from pence to pounds. Partitioning / distributive law, e.g. 28 x 4 can be split up into 25 x 4 add 3 x 4 or 30 x 4 subtract 2 x 4. Moving digits ITP Ensure that the setting out is accurate. 754 – 86 = 668 Take away (left) Recap on the finding of remainders on the number line. Pupils to explain the effect of multiplying by 10 and 100 Addition to be done mentally. HTU and TU x U -6 -80 ____________________________________ 668 674 754 Divide any integer up to 1000 by 10 “900 ÷ 10 = 90 because the digits move one place to the right” Ensure that all calculation is checked before started for any other possible ‘tricky’ bits. “7 add 5 equals 12. That’s 2 units and 1 ten to carry over. 80 add 70 equals 150 and the one ten to carry makes 160. That’s 6 tens and 100 to carry over. 500 add 400 equals 900 and the one hundred to carry makes 1000” Division Record using grid notation and expanded short multiplication. 21 ÷ 5 “What do I know? I know that 21 is not a multiple of 5, so there will be a remainder.” DIVISION WITH REMAINDERS Use problems in contexts that require the November 2016 answer to be rounded up or down following the remainder. Or Eg 35 children to sleep four to a tent. How many tents do we need? Or Find the difference (right) +4 +10 +654 __________________________________ 86 90 100 754 Decomposition (Continue with Diennes and/or money as appropriate) 754 - 86 700 600 50 80 60 4 6 8 346 x9 54 (9 x 6) 360 (9 x 40) 2700 (9 x 300) 31 1 4 11 Continue to use partitioning/re-arranging method. Decision making 79 70 60 50 Children investigate statements and solve word problems using appropriate methods. Children are also given examples of x9 and encouraged to think about using methods such as x10 and subtracting x1. 79 ÷ 3 = ‘What do I know about the divisor/3 x tables?’ “I know 3 x 10 = 30.” 20 ÷3 9 19 29 = 6 r1 Fractions relate to division. ÷ 4 is the same as halve and halve again. = 668 Approximate answer first using multiplication facts Recognise that division is non-commutative. 754 - 86 600 140 14 80 6 600 60 8 Know that a number cannot be divided by 0. = 668 Begin to use informal method for TU by U November 2016 division (additive chunking/chunking up). Informal recording for division NUMBER BOARDS “It’s tricky to take 6 from 4 and 80 from 50. I need to rearrange the number. I will exchange one ten from 50 which leaves 40 and makes 14 in the units. 40 to subtract 80 is tricky. I will exchange one hundred from 700 and make 140. 14 subtract 6 equals 8. 140 subtract 80 equals 60 and 600 subtract 0 equals 600.” Decomposition £ 8.95 -4.38 = £ 8 . 80 15 4 . 30 8 4 . 50 7 =4.57 96 6 “What do I know? 6 x 10 = 60” 60 36 10 6 96 6 = 16 “What do I know? Set up partial multiple table: 1 2 4 10 5 6 12 24 60 30 84 ÷ 7 = 80 + 4 70 + 14 10 + 2 = 12 November 2016 Emphasis on language of place value, i.e. 14 units subtract 6 units, 14 tens subtract 8 tens, and 6 hundreds subtract 2 hundreds. Use informal method for ÷ with bigger numbers using knowledge of multiples. 387 ÷ 6 = 380 + 7 370 + 17 360 + 27 = 64 r 3 60 + 4 ‘I know that 6 x 6 360’. = 36 so 60 x 6 will be Moving towards using known facts to recognise multiples. 387 ÷ 6 = 360 + 27 60 + 4 = 64 r 3 Begin to use Short division with ‘bus stop’ notation November 2016 “483 divided by 7. 4 hundreds cannot be shared equally between 7, so exchange the 100s for 40 tens. I now have 48 tens which shared equally between 7 is 6 with a remainder of 6 tens. Exchange the 6 tens for 60 units, we now have 63 units. 63 divided equally between 7 equals 9. The answer is 69.” Use Diennes or place value equipment to model Addition Subtraction Add with increasingly large numbers using the compact method. Extend methods to include decimals to two decimal places. Subtract with increasingly large numbers using the compact method. + 124.94 7.25 132.19 11 Stage F (Y5/6) Multiplication Th HTU , HTU , TU x TU and U Division Know division facts corresponding to tables up to 12 x 12 and be able to apply them. HTU x U Extend methods to include decimals to two decimal places. TU x TU Use the relationship between multiplication and division 28 x 27 Dividing up to 10,000 by 10/100 Check with inverse operation. Use of November 2016 calculator. Continue to use: Short division with ‘bus stop’ notation Addition to be done mentally or across followed by column addition. 28 x 27 56 (7x8) 140 (7 x20) 160 (20x8) 400 (20x20) 756 28 X 27 = 756 £2.73 x 3 £2.73 x 3 = 273p x 3 Followed by appropriate addition calculation. 273p x 3 = 819p = £8.19 “483 divided by 7. 4 hundreds cannot be shared equally between 7, so exchange the 100s for 40 tens. I now have 48 tens which November 2016 4346 x 8 = 34768 32000 2400 320 + 48 34768 4346 x 8 48 (8x6) 320 (8x40) 2400 (8 x300) 32000 (8x4000) 34768 Leading to short multiplication shared equally between 7 is 6 with a remainder of 6 tens. Exchange the 6 tens for 60 units, we now have 63 units. 63 divided equally between 7 equals 9. The answer is 69.” Use Diennes or place value equipment to model Express the quotient as a fraction or decimal. e.g. 486 ÷ 8 = 60 r 6 Fraction 60 6 8 Decimal 60.75 DIVISION WITH REMAINDERS PPT (example given below) 17 ÷ 5 “What do I know? 17 is not a multiple of 5”. November 2016 3 2 = 3.4 5 From knowledge of decimal/fraction equivalents or by converting two fifths into four tenths Decision making Children investigate statements and solve word problems using appropriate methods. Children investigate alternative methods such as compensation strategies and doubling and halving and discuss when these might be most appropriate and efficient. Examples: 24x99 could be done using the grid method, but could also be calculated by x100 and subtracting 24x1. 24 x25 could be done using the grid method, but could also be calculated Decision making Word problems, e.g. 200 people attended a concert. 1/5 of the people had complimentary tickets. The rest paid £7.50 each. How much money was collected from selling tickets? Money and measures, e.g. Which is longer: 3 /4 of an hour or 2500 seconds? Every day scenarios, e.g. Peter's family have a meal out to celebrate his birthday. The meal costs £52 and the restaurant adds a 15% service charge. How much is the bill altogether November 2016 by 24x100, halving to find x50 and halving again to find x 25. or using doubling and halving, 24 x25=12x50 =6 x100 Partitioning method for HTU 847 ÷ 7 “What do I know? I know 7x12 = 84 so 7 x 120 = 840” Problem solving Work out 575 ÷ 25, explaining your method. Peter says that, if you want to divide a number by 12, you can divide it by 4 then by 3. Is he right? Explain how you know. Work out 768 ÷ 12 using Peter's method and using another method. Do you get the same answer? How many 35p packets of stickers can I buy with £5? Explain how you know. Coaches have 56 seats for passengers. How many coaches are needed to take 275 people on a trip? November 2016 Complete this calculation: 943 ÷ 41 =2 Work out whether or not 29 is a factor of 811. Addition Promote decision making so that pupils choose an appropriate method/strategy. Continue the use of informal methods and number lines. Ensure understanding of standard written method. Practice ThHTU + ThHTU then calculations with any number of digits. Subtraction ThHTU – ThHTU then any number of digits. Appropriate use of a calculator including interpretation of displays. Money, measures and real life contexts. 6467 – 2684 Approximate using the most significant digits and have a feel for the ‘whole’ number. Stage G (Y6) Multiplication ThHTU x U and HTU x TU Division Multiplication of decimals Know all multiplication facts and corresponding division facts to 12 x 12 and beyond and be able to apply them. TU x TU Explain the effect of dividing by 000 78 x 42 16 (2 x 8) 140 (2 x 70) 320 (40 x 8) +2800 (40 x 70) 3276 1 Extend methods to include HTU ÷ TU Continue to use the short division method when the two digit divisor is up to 12 or is a easily recognisable multiple eg 20, 25 or 50. Compact (long) http://mathsonline.org/pages/longmult.html Appropriate teaching/use of the calculator including interpreting the display, eg money or measures. Calculator display 0.37 is then interpreted as 37p in the context of money. Remind 4p = 0.04 Calculator display £1.4 is interpreted as £1.40 324.9 – 7.25 78 X42 156 1 + 3120 3276 Use a calculator appropriately, approximating first Use of calculator for interpreting the November 2016 7648 + 1486 9134 111 Decimal points are fixed on the line with digits in the squares. 124.9 + 7.25 124.90 + 7.25 132.15 11 quotient by entering a fraction to find the decimal equivalent. = 13 .6 – 2.8 http://mathsonline.org/pages/longdiv.html +0.2 +10.6 __________________________________ 2.8 3 13.6 Use long division only with pupils who are secure with number sense and place value. 384 16 13.6 – 2.8 = 10.8 “What do I know about the divisor?” Record partial tables. leading to Decimals - fill ‘empty columns’ with zeros. Long division 14.6 – 2.76 __24 16 ) 3864 – 32 64 (thinking not generally recorded) (38÷16=2 r 6; 2x16=32) (bring the 4 down) (16 into 64=4; 4x16=64) – 64 0 (no remainder) Involve decimals, money and measures through approximation and appropriate use of the calculator. Addition either mentally or by column addition Decimals. Teach children how to use known November 2016 facts to build new facts according to the place value required, e.g. 3x4 =12 3x0.4 = 1.2 3x0.04 = 0.12 0.75 x 6 = 4.2 0.05 x 6 = 0.3 0.75 x 6 = 4.5 0.7 x 6 Grid method based upon very secure place value. Problem Solving Mike works out that 14 × 12 = 168. What is 14 × 1.2? How do you know? Use a written method to calculate 24 × 13. What do you need to change to show a similar method to work out 2.4 × 13? Use a written method to find the area of a swimming pool which is 25 m long and 7.5 m wide. Complete the missing sections to work out 35 Continue to make use of partitioning and the number line for repeated addition where appropriate. 944 ÷ 22 = November 2016 × 2.1: Which is closer to 100: 5.2 × 17 or 7.2 × 15? Use written methods to prove your answer. What do I know about the divisor? 440 ( 22 x 20) 880 (22 x 40) 944 ÷ 22 = 42 r 20 Express the remainder as a fraction or decimal. Problem Solving : Division giving a decimal answer, e.g. Divide 9 by 5 giving your answer as a decimal. Missing number calculations, e.g. = 0.04; 0.6 × ÷8 = 4.2 November 2016
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