Year 6 Autumn 1 Week 3 – Mental and Written Multiplication in the Context of Time
Main Learning
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Multiply multi-digit numbers up to 4 digits by a two-digit whole number using the formal written
method of long multiplication.
Multiply one-digit numbers with up to two decimal places by whole numbers.
Perform mental calculations, including with mixed operations and large numbers and decimals.
Choose an appropriate strategy to solve a calculation based upon the numbers involved (recall a
known fact, calculate mentally, use a jotting, written method).
Select a mental strategy appropriate for the numbers involved in the calculation.
Solve problems involving addition, subtraction, multiplication and division.
Express missing number problems algebraically.
Find pairs of numbers that satisfy an equation with two unknowns.
Use, read, write and convert between standard units, converting measurements of time from a
smaller unit to a larger unit, and vice versa.
Use estimation and inverse to check answers to calculations and determine, in the context of a
problem, an appropriate degree of accuracy.
Solve problems which require answers to be rounded to specified degrees of accuracy.
Success Criteria
Practice and Consolidation
Children will benefit from being given a range of calculations, some of which may be carried out
mentally, some using a jotting and some using a written method.
Which Method is Best?
Using Known Facts
ICT
Multiplication Grid Instructions
Mathematics - Planning Support © Lancashire County Council (2015)
Time Conversion
Vocabulary
lots of, groups of, times, multiply, multiplication, multiplied by, multiple of,
product, once, twice, three times………. ten times as (big, long, wide etc.)
inverse, hour, minute, second, o’clock, half past, quarter to, quarter past,
digital, analogue, clock, watch, timer, 24-hour clock, 12-hour clock,
Greenwich Mean Time, British Summer Time, International Date Line
Modelling
The children continue to relate their
understanding of multiplication as
repeated addition or scaling, to formal
written methods.
These should be set out in the school’s
agreed progression towards written
calculations policy.
An example can be found here.
Number lines are an effective model for mental calculation strategies.
They allow children to see where
numbers are in relation to each other
and offer guidance on decision making.
These should be set out in the school’s
agreed progression towards mental
calculations.
An example can be found here.
Children should be using their knowledge of multiplication to convert
between units of time. A visual model may support children in
understanding why multiplication is necessary.
How many hours
Converting minutes to seconds by multiplying by 60.
are in two weeks?
Converting hours to minutes by multiplying by 60.
Converting days to hours by multiplying by 24.
= 1 day or
Converting weeks to days by multiplying by 7.
24 hours
Converting years to days by multiplying by 365.
24 24 24 24 24 24 24
Using and Applying
Contextual Learning
Express the following
Wednesday
Thursday
in as many different
ways as you can.
Consider all the units of time you could convert this into.
Kim is thinking
Friday
Saturday
I know that 137 x 28 = 3836.
How could I use this to work out:
138 x 28
137 x 27
Write in the missing digits.
Challenge 70
A Bit Fishy
323 × _ 7 = 1518_
The main context for the multiplication learning this week is converting units of time.
However, other contexts may include money, other measures and real life problems. This
may include calculating area and perimeter and should include decimals.
How many hours in a week?
Summer holidays last for 6 weeks. How many days is that?
th
How many days have you been alive on your 11 birthday?
185 people go to the school concert. They pay 75p each.
How much ticket money is collected?
A rectangle measures eleven centimetres by twenty centimetres. What is its area?
Exercise books are 0.8cm thick. A pile of 9 exercise books is on the table.
How thick is the pile?
Gym mats are 1.6 metres long. If 5 mats are placed end to end,
what total length will they make?
£ to $
Conversion of currency is also a good context. For example, £1 is equal to about $1.4.
What is the approximate value of £5 in US dollars?
A film last 200 minutes. How many possible
start and end times can you think of?
Fred says:
START
?
There are 1440 minutes
in one day.
END
?
The End
Explain how he has worked this out.
Would you use a mental (including with a jotting) or written method to solve these?
i) 0.7 x 0.2 ii) 19 x 5 iii) 123 x 5 iv) 234 x 2 v) 5.65 x 10 vi) 23 x 45 vii) 23 x 99 viii) 19 x 3
Explain your choice.
Complete the missing sections to work out 35 × 2.1
Assessment
How does your knowledge of 56 ÷ 7 help you to calculate 0.56 ÷ 7?
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?
Find the area of a swimming pool which is 25 m long and 7.5 m wide.
How many hours in a fortnight?
□□ x □ = 380
Find the missing numbers.
Which is closer to 100: 5.2 × 17 or 7.2 × 15? Use a written method to prove your answer.
What day of the week will it be 100 days from today?
I’m thinking of two consecutive numbers. Their product is 2070. What are the two
numbers?
Mathematics - Planning Support © Lancashire County Council (2015)