All Product Catalog 2024

B1 Lesson Plans 46 ©MathTeachersPress, Inc.Reproduction by anymeans is strictly prohibited. 46 9. The famous 40 thieves are chasing Aladdin.If he outruns 14 of them, howmany are still chasing him? __________ 10. Aladdinwalks down into the cave.If there are 97 steps to the bottom, and he haswalked down 58, howmany more are left? __________ Draw a picturewith base ten blocks to explain how to subtract 41 – 15. Use thewords “ones place”and “tens place”to explain. Strategies:Find the Pattern 1. – 26 ______ 5. 73 – 17 ______ 6. 80 – 27 ______ 7. 56 – 28 ______ 8. 74 – 35 ______ Solve. Second, remove the smaller number. Therewere 62 students on the playground.Then 38 students went back inside to class.How many studentswere left? 56 53 28 39 26 thieves 39 steps Objective: To subtract 2-digit numbers, with and without regrouping. Materials: Base ten blocks, Place Value Mats (Masters 1 and 2), red and green crayons Bus Stops, Gomi, Taro (Activity 46) Aladdin (Any version) Subtraction on a Place Value Mat Each student or small group should have base ten blocks and Place Value Mats. Tell several subtraction stories aloud. For each problem, have students follow the steps in problem solving, use base ten blocks on a Place Value Mat and record their work with paper and pencil. Write on the board: There are 32 students in the class. 15 of the students are girls. How many are boys? Show 32 on your Place Value Mat: How can we take away 5 ones when there are only 2 ones on the mat? Give students time to discuss and share their ideas. (Exchange 1 ten for 10 ones. Now there are 2 tens and 12 ones. Then, remove 1 ten and 5 ones.) Ask volunteers to explain what was done with the blocks for each step. Record the information on the board as the student explains each action. Show how to record the problem: 2 12 32 15 17 What is the action in this problem? ( Subtraction.) Together, read through the information at the top of the page. Demonstrate the “borrowing” on a Place Value Mat as you work through the problem 62 – 38. Do problem 1 with the class, having a volunteer explain how she used her base ten blocks to find the answer. Write an “R” above the other problems in the first row that will require regrouping. (The third problem will not have an R.) Have students work in pairs to complete the remaining problems in the first row with blocks. How do you know if the problem requires regrouping? (If the ones-place digit in the top number is smaller than the ones-place digit in the bottom number, then you must regroup.) If you can see the regrouping in your head, try the second row without blocks. Tens Ones Read to Me Have students take turns showing one of the problems with base ten blocks as the teacher walks around and identifies students who are ready to solve the problem without base ten blocks. Before completing the bottom word problems, ask the students to recall the story of Aladdin . Remind them that math will appear in other subjects and in everyday life and that understanding math can help them succeed in other subjects and in daily life. Assessment Each small group should have base ten blocks and red and green crayons. Students will use crayons to show whether the problem requires regrouping. They can color the ones digit in the minuend green if no regrouping is required or red if regrouping is required. Present these problems: 73 53 – 28 – 31 Show me how to solve the first problem. Tell me what you are doing with the blocks. Show me how you record the problem. Repeat with the second problem. When we subtract, what is the pattern for borrowing? (Subtract the ones. If you need more ones to be able to subtract, regroup or trade 1 ten for 10 ones. Subtract the tens from the number of tens left after the trade.) S KILL B UILDERS 15-6, 15-7 © MathTeachers Press, Inc.Reproduction by any means is strictly prohibited. 46 9. The famous 40 thieves are chasing Aladdin. If he outruns 14 of them, how many are still chasing him? __________ 10. Aladdin walks down into the cave. If there are 97 steps to the bottom, and he has walked down 58, how many more are left? __________ Draw a picture with base ten blocks to explain how to subtract 41 – 15. Use the words “ones place” and “tens place” to explain. Strategies: Find the Pattern 1. 54 – 26 ______ 5. 73 – 17 ______ 2. 83 – 18 ______ 6. 80 – 27 ______ 3. 94 – 21 ______ 7. 56 – 28 ______ 4. 65 – 16 ______ 8. 74 – 35 ______ Solve. Tens Ones First, build the larger number. Second, remove the smaller number. There are not enough ones. Exchange 1 ten for 10 ones. There were 62 students on the playground. Then 38 students went back inside to class. How many students were left? Tens Ones Tens Ones Third, you can now remove 8 ones and 3 tens. 62 – 38 2 4 12 5 62 – 38 Record the problem this way. Students develop conceptual understanding and experience success as they use manipulatives to explore, discover, and communicate patterns. These successful experiences build confidence, motivate students, and improve attitudes toward math. Base ten blocks are used to develop conceptual understanding of the most difficult objective in the primary grades—2-digit subtraction with regrouping. Confidence from Understanding Lesson from Teacher Manual Student Book Page 7 www.movingwithmath.com