Grade 4 Mathematics Lesson Plan Date: June 27 (Wed.), 2007, Period 5 Teachers A: Masako Adachi (Classroom 1) B: Akihiko Suzuki (Classroom 2) C: Masako Koizumi (Math Open) Research Theme: Nurturing students to become people who can be trusted in an international society: Developing instruction that will foster students’ ability to communicate 1. Name of the unit: 2. About the unit Let’s think about how to divide Flow of the contents Grade 3 Grade 4 (3) Division • Meanings of division and the division sign • Division that can be solved by using the basic multiplication facts (no remainder) This unit: The division algorithm (1) • The division algorithm for a 2- or 3-digit number divided by a 1-digit number • Methods of calculating math sentences with o both multiplication and division operations o consecutive division Extending the meanings of division and “times as much” (1st and 3rd uses of times as much) (7) Division with remainders • Division that can be solved by using the basic multiplication facts (with remainders) • How to check answers • Meaning of remainders Division algorithm (2) • Dividing by multiples of 10 • Division algorithm for 2- or 3-digit numbers ÷ 1-digit numbers • How to check answers for division • Meaning of a tentative quotient and how to adjust it • Properties of division Grade 5 (2) Multiplication and division of decimals (I) Division of whole numbers with decimal quotients and dividing decimals by whole numbers (4) Multiplication and division of decimals (II) • Meaning of dividing by a decimal and how to calculate • The division algorithm for dividing whole numbers and s by decimals (6) Fractions and Decimals • Quotients of whole numbers can always be written as fractions This lesson plan is originally written in Japanese and translated into English by the Global Education Resources for the Lesson Study Immersion Program in Japan, June 21- July 5, 2007. © 2007 Global Education Resources L.L.C. All rights reserved. Goals of the unit Students will understand the division algorithm for dividing 2- and 3-digit numbers by 1-digit numbers and be able to use it appropriately. [Interest, Desire, Attitude] • Students will try to use their previous study of division to think about how to divide 2- and 3-digit numbers by 1-digit number. [Mathematical Thinking] • Students will be able to clearly explain that the division algorithm proceeds from the tens digit and then the ones when you are divide 2-digit numbers by 1-digit numbers. • Students will be able to clearly explain that the division algorithm for dividing 3-digit numbers by 1-digit numbers works in the same way as was learned previously (2-digit ÷ 1-digit). [Representations, Procedures] • Students will be able to accurately calculate 2- and 3-digit numbers ÷ 1-digit numbers. • Students will be able to mentally calculate 2- and 3-digit numbers ÷ 1-digit numbers with 2-digit quotients. [Knowledge, Understanding] • Students will understand how to divide 2- and 3-digit numbers by 1-digit numbers using the division algorithm. • Students will understand that they can use division to determine “times as much”. • Students will understand that one math sentence may be used even when situations involve both multiplication and division or two consecutive divisions. Current state of the students According to the results of the readiness test, virtually all students can accurately calculate division problems that use the basic multiplication facts once, which was studied in Grade 3. Although a few students missed remainders on some problems, all problems were correctly answered by at least 97% of the students. There were 2 problems that involve the ideas to be studied in Grade 4: (1) 40 ÷ 2, and (2) 600 ÷ 3. Although it seems like students should be able to anticipate the answers, the success rates were (1) 85% and (2) 70%. Moreover, for both problems, 9% of the students left them blank. Given the success rates on the items involving previously learned topics, we would like to plan a lesson that will take advantage of their ability to read and interpret math sentences and further extend this ability. However, in the prior unit on circles and spheres, some students had difficulty using compasses appropriately, indicating that some children still lack fine motor skills. Moreover, some students’ understanding may still be rather superficial, and their computational skills are more advanced than their ability to think and reason. Therefore, we want to provide opportunities for students to enjoy solving problems by thinking carefully and manipulating objects. This lesson plan is originally written in Japanese and translated into English by the Global Education Resources for the Lesson Study Immersion Program in Japan, June 21- July 5, 2007. © 2007 Global Education Resources L.L.C. All rights reserved. 3. Abilities we would like to foster in this unit and special instructional strategies Target abilities for this unit 1. To make well-grounded explanations [Using prior understanding as the foundation for reasoning] • Ability to use properties of division in explanations instead of just learning the algorithm procedurally. • Ability to explain the reasons for the steps of the division algorithm instead of simply reciting, “estimate, multiply, subtract, and bring-down.” 2. To communicate effectively [Creating concise representations, diagrams and writing] • Ability to describe situations involving “times as much” and division appropriately, utilizing diagrams and math sentences effectively. 3. To perceive and reason from multiple perspectives [Selecting more appropriate reasoning] • Ability to interpret math sentences to know how others thought about problems involving both multiplication and division. • Ability to select more appropriate reasoning using the criteria: efficient, simple, and accurate (ESA). Instructional strategies 1. Level-raising strategies The first 3 lessons of the unit will be used to discover the properties of division. To improve students’ ability to interpret math sentences, we will frequently have them sort shared solutions and strategies. Repeatedly ask students to use diagrams and math sentences as they explain. To make number lines a more familiar tool, we will frequently ask students to label the number lines. Use missing number problems to promote algebraic reasoning while exploring the algorithm and the properties of division. Employ small group instruction. 2. Effective learning tasks • Use carefully selected numbers in the task to make it more realistic (problem involving both x and ÷). • Use a familiar setting to make the task more interesting (times as much). • Use a new type of problem to think deeply about the division algorithm and the properties of division (missing number). 3. Question posing • In all lessons, include as many questions as possible to encourage students to look for more appropriate reasoning, foe example, “Which operation is more ‘ESA’ to calculate times as much/” or “Which strategy is more ‘ESA’?” • Carefully sequence students’ strategies to be shared publicly, and ask students to share their observations so that they may recognize similarities in reasoning. 4. Interpreting students’ reasoning. • Throughout every lesson, ask students to record their thinking in their notes to capture the change in their thinking. • Have students write in a learning journal. Note: Arrows indicate how particular strategies may foster specific target abilitie This lesson plan is originally written in Japanese and translated into English by the Global Education Resources for the Lesson Study Immersion Program in Japan, June 21- July 5, 2007. © 2007 Global Education Resources L.L.C. All rights reserved. 3. Group research – examining the research theme (1) On “times as much” (2) On the use of number line model (3) Proposals on “times as much” and number line model This lesson plan is originally written in Japanese and translated into English by the Global Education Resources for the Lesson Study Immersion Program in Japan, June 21- July 5, 2007. © 2007 Global Education Resources L.L.C. All rights reserved. 4. Plan of instruction Plan for Class 1 (Ms. Adachi) # Goals Learning Task (1) Properties of division 1 Readiness test Administer the test. To discover patterns in • To discover patterns division when the from the math dividend stays constant. sentence, 24÷○=□. 2 To discover patterns in • To discover patterns division when the divisor from the math stays constant. sentence, □÷ 3 = ○. 3 To discover patterns in division when the quotient stays constant. • To discover patterns from the math sentence, □÷ ○ = 3. (2) Dividing multiples of 10 and 100 4/ • To understand how the • To think about how to 5 division algorithm calculate 80 ÷ 4. works when dividing • To practice similar multiples of 10 and problems. 100 by 1-digit • To think about how to numbers. calculate 240 ÷ 6. • To practice similar problems. (3) Division algorithm (I) [2-digit ÷ 1-digit] 6/ • To understand how the • To understand the the 7 division algorithm problem situation and works when dividing write a math sentence. 2-digit numbers by • To think about how to 1-digit numbers (no calculate 52 ÷ 4. remainder) • To summarize how the algorithm works with 52 ÷ 4. • To check the answer for 52 ÷ 4. • To practice the algorithm. Evaluation Preassessment • Are Ss trying to discover patterns in division? (Interest) • Can Ss discover that when the dividend becomes △ times as much, the quotient also becomes △ times as much (constant divisor)? (Mathematical Thinking) • Can Ss discover patterns and represent them clearly (constant quotient)? (Representation) • Can Ss consider the dividends using 10 as a unit and apply the basic multiplication facts to find the quotient? (Math Thinking) • Can Ss divide multiples of 10 and 100 by a 1-digit number by using the relative sizes of the dividends? (Representations) Class 2 (Suzuki) (1) (1) – 1 Open (1) (1) – 1 (1) – 2 (1) – 2 (1) – 3 (1) – 3 (2) (2) – 4/5 (2) (2) (Koizumi) (3) (3) • Are Ss trying to use their (3) – (3) – prior learning to think 6/7 6/7 about how to calculate 2-digit ÷ 1-digit? (Interest) • Can Ss explain clearly that the division algorithm should proceed from the tens digit and then the ones when you are dividing 2-digit numbers by 1-digit numbers? (Mathematical Thinking) 8 To understand how the • To understand the • Can Ss. calculate 2-digit ÷ (3) – 8 (3) – 8 division algorithm works problem situation and 1-digit using the division when dividing 2-digit write a math sentence. algorithm (with remainder numbers by 1-digit • To think about how to and neither place is numbers (with use the division divisible)? remainder, neither place algorithm for 76 ÷ 3. (Representations) is divisible). • To know what the • Do students know how to “quotient” is. divide 2-digit numbers by • To check the answer 1-digit numbers (with This lesson plan is originally written in Japanese and translated into English by the Global Education Resources for the Lesson Study Immersion Program in Japan, June 21- July 5, 2007. © 2007 Global Education Resources L.L.C. All rights reserved. for 76 ÷ 3. • To practice similar problems. • To read the “Math Corner” in the text and learn about the terms, “sum,” “difference,” and “product.” • To think about how to calculate 86 ÷ 4 and 62 ÷ 3. • To practice similar problems. • To practice dividing 2-digit numbers by 1-digit numbers (with remainder and solvable by using the basic multiplication facts once). 9 remainder and neither place is divisible)? (Knowledge) • To understand how the • Can Ss divide 2-digit division algorithm numbers by 1-digit works when dividing numbers (with remainder 2-digit numbers by and solvable by using the 1-digit numbers (with basic multiplication facts remainder but the tens once)? (Representations) place is divisible). • Do Ss understand how the • To be able to divide division algorithm works 2-digit numbers by when dividing 2-digit 1-digit numbers by numbers by 1-digit using the algorithm numbers (with remainder (with remainder and but the tens place is solvable by using the divisible)? (Knowledge) basic multiplication facts once). (4) Patterns in the division algorithm and math sentences involving division 10 / • To understand that • By using the • Are Ss thinking logically 11 there are patterns in relationships, divisor > as they look for the digit the division algorithm remainder and quotient in each □? (Mathematical through examination x divisor < dividend, Thinking) of missing-digit find the numerals that • Can Ss use the remainder problems. (Lesson B go in the □. to figure out the quotient? in Class 2) • By thinking about the (Representations) digit in the ones place • Can Ss discover the of the dividend, relationship between the explore the dividend and the divisor relationship between by looking at the three the quotient and the problems? dividend. (3) – 9 (3) – 9 (5) – 14 (4) – 12 (5) - 15 (4) - 13 12 (4) – 10 [lesson A] (5) – 14 [lesson C] • To understand that situations that involve both multiplication and division or two consecutive divisions may be written as single math sentences. (Lesson A in Class 1) • Determine the number of pencils each person will receive when 4 dozen pencils are shared among 6 people. • To understand that two-step problems involving both multiplication and division or two divisions can be written as single math sentences. • Can Ss explain why situations that involve both multiplication and division or two consecutive divisions can be written as single math sentences? (Mathematical Thinking) • Do Ss understand how to calculate math sentences that contain both multiplication and division or two consecutive divisions? This lesson plan is originally written in Japanese and translated into English by the Global Education Resources for the Lesson Study Immersion Program in Japan, June 21- July 5, 2007. © 2007 Global Education Resources L.L.C. All rights reserved. 13 • To master what they have been studying so far. • To practice problems involving both multiplication and division and two consecutive divisions. • To complete “Let’s master” in the textbook. (Knowledge) • Are Ss appropriately using what they have learned so far to solve problems correctly? (Representations) (4) – 11 (5) – 15 (5) Calculation involving “times as much” 14 To understand that • To think about what • Are Ss trying to utilize (4) – 12 (4) – 10 division is used to operation should be diagrams such as number determine how many used to determine how lines to grasp relationships times as much a given many times as long 15 among quantities? quantity is as the base m is as 3m by using (Interest) quantity. (Lesson C in diagrams. • Do Ss understand that Open) • To learn that division division may be used to can be used to determine how many determine how many times as much? times as much, and to (Knowledge) work on application problems. 15 • To understand that • To think about what • Are Ss thinking about (4) – 13 (4) – 11 division can be used operation to use to math sentences that will to determine the base determine the base help them determine the quantity given the quantity given 72 kg is base quantity? compared quantity, 6 times as heavy as the (Mathematical Thinking) and how many times base quantity. • Do Ss understand that it is as much as the • To learn that division division may be used to base quantity. can be used to determine the base determine the base quantity? (Knowledge) quantity, and to work on application problems. (6) Division (3) (3-digit ÷ 1-digit) 16 • To understand how • To understand the • Are Ss thinking about (6) – 16 (6) – 16 the division algorithm problem situation and 3-digit ÷ 1-digit in the works when dividing write a math sentence. same manner as 2-digit ÷ 3-digit numbers by • To think about how to 1-digit? (Mathematical 1-digit numbers (no use the division Thinking) remainder, but the algorithm for 734 ÷ 5. • Can Ss accurately tens and hundreds • To summarize how to calculate 3-digit places are not use the division ÷1-digit=3-digit? divisible). algorithm to calculate (Representations) 734 ÷ 5. • To practice similar problems. 17 • To understand how • To think about how to • Can Ss calculate 3-digit ÷ (6) – 17 (6) – 17 the division algorithm use the division 1-digit = 3-digit (with 0 in works when dividing algorithm to calculate the quotient)? 3-digit numbers by 843 ÷ 4 and 619 ÷ 3. (Representations) 1-digit numbers (with • To practice similar 0 in the quotient). problems. 18 • To understand how • To understand the • Are Ss trying to relate to (6) – 18 (6) – 18 the division algorithm problem situation and what they have learned works when dividing write a math sentence. previously? (Interest) 3-digit numbers by • To think about how to • Can Ss accurately This lesson plan is originally written in Japanese and translated into English by the Global Education Resources for the Lesson Study Immersion Program in Japan, June 21- July 5, 2007. © 2007 Global Education Resources L.L.C. All rights reserved. 1-digit numbers (2-digit quotient, i.e., the leading digit < divisor). (7) Mental computation 19 • To understand how to mentally calculate 2-digit ÷ 1-digit = 1-digit and divisions of multiples of 10 and 100 by 1-digit numbers, and to be able to actually perform such calculations. use the division algorithm for 256 ÷ 4. • To summarize how to use the division algorithm to calculate 256 ÷ 4. • To check the answer for 256 ÷ 4. • To practice similar problems. calculate 3-digit ÷ 1-digit = 2-digit? (Representations) • Do Ss understand how to use long division to calculate 3-digit ÷ 1-digit = 2-digit? (Knowledge) • To think about how to calculate 74 ÷ 2 mentally. • To practice similar problems. • To think about how to calculate 740 ÷ 2 mentally. • To practice similar problems. • Are students connecting mental calculation of 2- or 3-digit ÷ 1-digit to their prior learning by decomposing the dividends or considering the relative sizes of the dividends (i.e., using 10 or 100 as units)? (Mathematical Thinking) • Can Ss mentally calculate 2- or 3-digit ÷ 1-digit? (Representations) [ 1 ~ 2 lessons ] • To complete the “Let’s • Do Ss understand the check” section of the contents? (Knowledge) textbook. (8) Summarizing 20 • To review and assess students’ understanding of the contents. To deepen students’ understanding of the division algorithm by working on “Challenge” on p. 96 of the textbook. (7) – 19 (7) – 19 (8) – 20 (8) - 20 This lesson plan is originally written in Japanese and translated into English by the Global Education Resources for the Lesson Study Immersion Program in Japan, June 21- July 5, 2007. © 2007 Global Education Resources L.L.C. All rights reserved. Lesson Plan B (Class #1, Ms. Adachi) 1. Goals of the lesson: • • Students will be able to write math sentences for problems that require both multiplication and division operations. Students will understand that even when both multiplication and division operations are involved, the situation can be represented in a single math sentence. 2. Flow of the lesson Steps Questions () Learning activities () Anticipated responses (C’s) 1. Understand the task. Read the problem. If you share dozen pencils among people, how many pencils will each person receive? What operation do we need? (Why?) Understand 2. Solve the problem. Let’s think about it in many different ways. Examine T1 There are 8 dozen pencils. 6 people will share the pencils. C1 Maybe multiplication. C2 Must be division because we are sharing equally. C3 I think we need both because we don’t know the number of pencils. C4 I have a question. Do we need to think about the number of pencils in the boxes? T2 The question says “how many pencils,” so we do have to think about the pencils in the boxes. C5 How many pencils are in the boxes? C6 It says 1 dozen, so there must be 12 pencils. C7 Should we draw a diagram? T3 It is up to you. If you think a diagram will be helpful, please draw it. Let’s work on this problem. Pay close attention to what operation you will be using. Individual problem solving C1 12 x 8 ÷ 6 = 16. Answer 16 pencils. (diagram) C2 12 x 8 = 96 96 ÷ 6 = 16 C3 12 ÷ 6 x 8 = 16 C4 12 ÷ 6 = 2 2 x 8 = 16 C5 8 ÷ 6 = 1 rem. 2 12 x 2 = 24 24 ÷ 6 = 4 12 x 1 = 12 12 + 4 = 16 C6 8 ÷ 6 = 1 rem. 2 (confuses 2 dozen and 2 pencils) 12 x 1 + 2 = 14 Answer 14 pencils. C7 When calculating the number of pencils, instead of (# of pencils/dozen) x (# of dozens), writes (# of boxes) x (# of pencils/dozen). C8 Makes computational errors while using one of the strategies for C1 ~ C4. C9 Only draws a diagram. C10 Cannot even get started. Points of consideration (*) Evaluation Strategies for improving communication () Materials: 8 dozens of pencils Problem that focuses students’ attention on the quantities in the situations. Problem statement is similar to familiar division situations. * C1 ~ C5 Encourage them to think about other ways to solve the problem. * Write mainly math sentences on the whiteboards. * It is ok if not everyone solves the problem correctly. C7 Points out that the multiplicand should be the number of pencils in a box. C8 Asks student to check his/her calculation. C9 Encourage student to think about what math sentences can be used. C10 Provide concrete objects to use. This lesson plan is originally written in Japanese and translated into English by the Global Education Resources for the Lesson Study Immersion Program in Japan, June 21- July 5, 2007. © 2007 Global Education Resources L.L.C. All rights reserved. 3. Think about more appropriate strategies. Let’s share our solutions. Look at all the solutions. Let’s organize these solutions. Let’s sort them according to their reasoning strategies. Listen to fellow classmates’ reasoning and compare solution methods. C1 Some of them start with 12 while others start with 8. C2 Some start with multiplication while others start with division. C3 Some have only one math sentence while others have 2. * There may not be enough space on the board to post all students’ work. Start with the students seated near the hallway, and have them move the whiteboards around to organize the solutions. * We will not sort the strategies based on the types of diagrams used. Deepen Example 1: C1, C2, C3, C4, C5, and C6 are all considered different. Example 2: Those with one math sentence and those with more than one. Example 3: Those that start with 8 and those that start with 12. Example 4: Those that use multiplication first and those that use division first. Example 5: Focus on the objects involved in the problem: those that shared pencils in each box first, those that shared the boxes first then dealt with the left over boxes, and those that figured out the total number of pencils first. C4 Some have different answers. Let’s explain. The answer for 2-C6 is 14 pencils. There is no computation error, is there? So, why is it different? T1 Is there any other solution that used the same reasoning as 2-C6? C5 2-C5. C6 They both found how many dozen pencils each person will get. T2 So is the problem the ways they looked at the remainders? C7 When we do 8 ÷ 6, we know that each person will receive 1 dozen, and there will be 2 dozen left. Since the remainder is not 2 pencils, I don’t think we can add 2 to 12 pencils. T3 So, the remainder tells us that there are 2 more dozen, or 24 pencils, left to be shared. We calculated how many dozen pencils each person receives, so the remainder should also be in dozens, as 2-C5 did. * If no one does 2-C6, suggest it as an example of an incorrect answer. (To understand the meaning of the remainder.) Use a callout and write, “First ,find how many dozen pencils there are for each person.” This lesson plan is originally written in Japanese and translated into English by the Global Education Resources for the Lesson Study Immersion Program in Japan, June 21- July 5, 2007. © 2007 Global Education Resources L.L.C. All rights reserved. Did you notice anything? 4. Summarize today’s lesson and reflect. Which reasoning or math sentence is the best? Let’s use “ESA.” T4 Now that we have sorted these solutions, let’s hear the explanation for each. C8 I will explain 2-C2. First, we calculated the total number of pencils. There are 96 pencils altogether. Then, we shared them equally among 6 people. C9 I will explain 2-C1. First, we calculated the total number of pencils, then we shared them among 6 people. C10 Their reasoning is the same. T6 So can we call both of them “the method that first calculates the total number of pencils”? C11 Yes. T7 2-C3, can you explain 2-C4’s solution? C12 First, we shared the pencils in each box. Each person will get 2 pencils. Since there are 8 dozen pencils, each person will get 8 times as many as 2 pencils, or 16 pencils. C13 I will explain 2-C3. The reasoning is exactly the same as 2-C4, but it is written in one math sentence. T8 OK, so it is just like 2-C1 and 2-C2. One of them uses one math sentence while the other uses 2 math sentences. So, what is the difference between 2-C1/2 and 2-C3/4? C14 The difference is whether you calculate the total number of pencils first or the number of pencils each person receives from each box first. Students will see the merit of writing one single math sentence. Summarize today’s lesson. Summarize It is easy to make a mistake when you use reasoning that involved remainders. C2 When you write one math sentence, it looks simpler. T1 Is it easier to see the reasoning and solution in one math sentence than 2 or more math sentences? Please write down what you think is the best approach. T2 When both multiplication and division are in one math sentence, can we start with the last operation? (Example, 8 x 6 ÷ 12.) C3 I don’t think we can because we will get different answers. T3 Let’s summarize. 2-C1 explains. Callout, “Share the total number of pencils.” 2-C2 explains. 2-C3 explains. Callout, “Calculate the number of pencils for each box first.” 2-C4 explains. Can Ss understand that the solution with one math sentence with both multiplication and division and the one with 2 math sentences are based on the same reasoning? (Math Thinking) Think using the criteria, “ESA.” C1 Do Ss understand how to calculate math sentences with both multiplication and division? (Knowledge) We can write one math sentence even when both multiplication and division are involved. Math sentences with both multiplication and division must be calculated in order from left to right. Let’s write a journal entry. C4 Writes his/her journal entry. This lesson plan is originally written in Japanese and translated into English by the Global Education Resources for the Lesson Study Immersion Program in Japan, June 21- July 5, 2007. © 2007 Global Education Resources L.L.C. All rights reserved. Lesson plan A (Class # 2, Mr. Suzuki) 2 lessons (today’s lesson / ) 1. Goals of the lesson • By thinking about the missing digits, students will reaffirm their understanding of the properties of division. (First half: By thinking about the missing digits, students will recognize the relationship, b > e.) (Second half: By thinking about the missing digits, students will understand that the properties of division can be observed in the procedure of the division algorithm.) 2. Flow of the lesson Steps Questions () Learning activities () Anticipated responses (C’s) 1. Understand the task. Read the problem. T1 We have been studying division of 2-digit numbers with remainders. Today’s lesson is based on that idea. Write the numerals from 1 to 4 in the boxes labeled A to D so that the division problem Points of consideration (*) Evaluation * Materials: Numeral cards (1 ~ 4 and 1 ~ 9), several sets and several copies of the problems (shown on the left) on cards. shown is correct. Understand In the boxes A ~ D, you need to write numerals 1 ~ 4. C1 Can we use them many times? C2 What should go in the other boxes? T2 You can use any numeral, but not everything will make the division problem correct. C3 I wonder if we can just pick numerals. T3 For each numeral, there is reason why it has to be in a specific box. For example, if you think about it very carefully, you will know that 1 can only go into C. You can use the numerals 1 4 once and only once. If you are not sure, you can try putting a numeral in a box and see what happens. * Some students may be hesitant getting started. It is important that students actually start trying. This lesson plan is originally written in Japanese and translated into English by the Global Education Resources for the Lesson Study Immersion Program in Japan, June 21- July 5, 2007. © 2007 Global Education Resources L.L.C. All rights reserved. 2. Solve the problem. Individual problem solving. C1 (correct) C2 * Explain how Ss can use the hint card (when you are not sure, you can open it up little by little). C3 Hint card 1. Examine C1 C2 C3 C4 C5 Correct answer. Understands Divisor > Remainder. Does not understand Divisor > Remainder. Tries putting numerals in the boxes. Cannot get started. ! 3. Think about why. I thought like this (incorrect answer). What do you think? Deepen How about these? They all have B > D. Listen to other students’ ideas and think about how to get the correct answer. Show 2-C3 on the board. C1 That’s not correct. C2 Since the remainder is greater than the divisor, I don’t think that is correct. C3 It has to be B > D. T1 Show answers like 2-C2 (show several of the same pattern at once). C1 If you do B x C, it will be greater than A in all of them. C2 You can’t subtract from A. T2 So what do we need to do? C3 Explain by moving the cards around: Since we can use each card once and only once, the only combinations that will make it possible to subtract is B = 3 and D = 2. So, the answer is, A = 4, B = 3, C = 1, and D = 2. Summarize T1 “We used the rule that the remainder must be less than the divisor and solved the problem systematically.” (Blackboard writing, too.) C1 What numerals go in the other boxes? Will 5, 6, 7, 8 and 9 work? What number can go into the remainder, D? (Let’s think about the remainder first.) 2. Which is larger, B or D? ( C3) 3. There is a numeral that cannot go into B. ( B " 1) 4. Try putting the numerals in any way. 5. Which is it, C < A or C > A? 6. B = 3 * The answer to be posted on the board will be prepared by the teacher. * Have a student who found the same answer as 2-C3 explain. (Point to focus.) Blackboard: B > D * All of them are incorrect answers. Are Ss reasoning logically to determine what numerals will go in the boxes? (Math Thinking) * Acknowledge students’ interest to explore further. This lesson plan is originally written in Japanese and translated into English by the Global Education Resources for the Lesson Study Immersion Program in Japan, June 21- July 5, 2007. © 2007 Global Education Resources L.L.C. All rights reserved. 1. Understand the task. Extension: Understand That is a very good question. What numerals will go in E and F? Think about a new problem. T1 We can use the numerals 1 to 9 in E and F, and we can use the same numeral at most twice. What patterns can you find when the division problem is correct? We are not changing 1, 2, 3, 4 that are already shown. E F 2. Individual problem solving E F I Extension: Examine (4) J G H K L Solve the problem individually. C1 Cannot get started. C2 I = 3 and G = 1. C3 Could do the same as C2, but after that just uses random trial and error. C4 Keeps trying to put different numerals in E and F. C5 I found one. By trial and error. C6 I found two. C7 I figured it out. It’s easy. There are 3 kinds. C8 Understand that the number (4) , “1H,” must be two more than a multiple of 3, and use that idea to find E and F. Answer A Answer B Answer C * We are not changing the numerals in A to D. Are Ss trying to examine whether their previous reasoning can be extended to determine the numerals for boxes E and F? (Interest) Hint card 1. What should be I? J = 0, isn’t it? 2. What should be G? 3. What can you say about “KL”? (K = 0 or 1). 4. How many more is the number “GH” than the number “KL”? What numeral can go into E? Use whiteboards. Can Ss figure out the quotient by focusing on the remainder? (Representations) 3. Look for patterns. Extension: Deepen Look at E (in the quotient) and the divisor, “4F.” Look for patterns from the solutions to the missing digit problem. Answer A Answer B Answer C (see above) C1 The number, “1H,” must be 3 more than a multiple of 3. So, 9 + 2 = 11, 12 + 2 = 14, 15 + 2 = 17 are the possibilities. So, F must be 1, 4, or 7, and E must be 3, 4, or 5. Display the three correct solutions. Can Ss discover the pattern between the dividend and the divisor from the three correct answers? (Math Thinking) C2 The quotients are increasing by 1. C3 The dividends are increasing by 3. C4 There are other patterns. 9, 12 and 15 are the 3’s facts in the multiplication table. C5 The numbers, (4), are also increasing by 3. This lesson plan is originally written in Japanese and translated into English by the Global Education Resources for the Lesson Study Immersion Program in Japan, June 21- July 5, 2007. © 2007 Global Education Resources L.L.C. All rights reserved. 4. Summarize the lesson. Summarize the patterns of division. T1 41 ÷ 3 = 13 rem. 2 44 ÷ 3 = 14 rem. 2 47 ÷ 3 = 15 rem. 2 (dividend) ÷ (divisor) = quotient + remainder Extension: Summarize C1 We did this before. C2 Even in the division algorithm, we have the same pattern we saw in the 3’s facts—when one number increases by 1 the other increases by 3. <Summary> When the quotient increases by 1, the quotient will increase by the divisor, 3. Let’s write today’s journal entry. C3 Write his/her journal entry. This lesson plan is originally written in Japanese and translated into English by the Global Education Resources for the Lesson Study Immersion Program in Japan, June 21- July 5, 2007. © 2007 Global Education Resources L.L.C. All rights reserved. Lesson Plan C (Mathematics Open Room, Ms. Koizumi – small group for mathematics) Goals of the lesson: Using a number line or tape diagram, students will think about methods to determine how many times as much the base number is as the given number. Flow of the lesson Steps Questions () Learning activities () Anticipated responses (C’s) 1. Understand the task for the lesson. I can swim 15 m without taking a breath. How many times as far as ______________ can I swim without taking a breath? Understand This is today’s problem. That’s true. _______ can swim 3m without taking a breath. C1 Something is wrong. C2 We need to know how many meters _____ can swim without taking a breath. C3 We can do this. Points of consideration (*) Evaluation Strategies for improving communication () At first, display the problem statement that does not include the base amount. Pose a problem that is appropriate for the season. * Help students pay attention to the base amount. * Make sure students understand that the base amount is 3 m. I can swim 15 m without taking a breath. _______ can swim 3 m without taking a breath. How many times as far can I swim without taking a breath as _______? 2. Solve the problem. Let’s use what we have already studied to figure out how many times as far as _______I can swim without taking a breath. Solve the problem using own strategies. * Prepare the worksheet. Cs Write their own strategies on the worksheet. * For those students who cannot even get started, provide tapes that are 3 cm and 15 cm so that they can draw a tape diagram. Examine Use multiplication to determine how many times. 3 x [5] = 15 5 times as far. 3x1=3 3m 3x2=6 6m 3x3=9 9m 3 x 4 = 12 12 m 3 x 5 = 15 15 m 5 times as far. Think, “how many sets of 3 m will make 15 m?” 15 ÷ 3 = 5, 5 times as far. Are students trying to solve the problem? (Interest) Can Ss solve the problem using their own ideas and represent it in a diagram, a math sentence, or a chart? (Mathematical Thinking) * Have students write their math sentences and diagrams on their whiteboards. This lesson plan is originally written in Japanese and translated into English by the Global Education Resources for the Lesson Study Immersion Program in Japan, June 21- July 5, 2007. © 2007 Global Education Resources L.L.C. All rights reserved. 3. Read other students’ ideas. Let’s look at all the solutions. I wonder if we can sort them? Deepen There is no space to show “times as much” on a number line, is there? 4. Summarize. Summarize When you are figuring out “how many times as much,” what operation should we use? Think “ESA.” Using the idea from today’s lesson, let’s try this problem. Compare their own ideas with other students’ ideas. Explain their own reasoning. Multiplication methods Division methods Number line methods It shows only m, doesn’t it? Where can we show “times as much”? Summarize today’s lesson on the worksheet. To find how many times as much, we can use division. Draw a number line model. Students will attempt the problem using what they learned in today’s lesson. Acknowledge and praise that they were able to solve the problem using many different ideas. Have students explain other students’ ideas, not their own. * If there is any strategy that cannot be grouped with others, or other students cannot figure out the strategy, have the student who came up with the strategy explain it. Based on students’ ideas, orchestrate the discussion so that students will recognize that different ideas can be summarized using number line models. * Make sure that students understand the importance of drawing a number line correctly and using 1 as the base of comparison. * Review how to draw a number line. Can Ss draw a number line correctly? (Mathematical Thinking) A mother whale is 24 m long. A baby whale is 6 m long. How many times as long is the mother whale as the baby whale? 5. Reflect on today’s lesson. Please write what you noticed or realized in today’s lesson. Write a journal entry. * Encourage students to write about the base amount in their journal entries. This lesson plan is originally written in Japanese and translated into English by the Global Education Resources for the Lesson Study Immersion Program in Japan, June 21- July 5, 2007. © 2007 Global Education Resources L.L.C. All rights reserved.
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