Lesson Plan : Subtraction with Regrouping
Teacher Name: | Meghan Trubiano |
Grade: | Grade 3 |
Subject: | Math |
Topic: | Introduction to 2 digit subtraction with regrouping. |
Content: | |
Goals: | After a teacher-directed math lesson, the students will: demonstrate how to regroup two-digit numbers and solve advanced subtraction problems with regrouping. Each student will use straw and cup manipulatives to demonstrate how to borrow from the tens place in order to solve the problem. Each student will regroup at an accuracy rate of at least 80%. |
Objectives: | When we finish today, you will be able to demonstrate how to regroup two-digit numbers by borrowing from the tens place." |
Materials: | an abacus, a set of straw and cup manipulatives for every child, overhead projector,ten strips and ones, and worksheets (enrichment and remedial to be included). |
Introduction: | 1. Explain that today we are going to learn how to regroup two-digit subtraction problems. 2. Remind students what subtraction is: "taking away" or subtracting two or more numbers to find the difference. 3. Have the regrouping rhyme written on the white board. More on top? No need to stop. More on the floor? Go next door, Get ten more. Numbers the same? Zero's the game. |
Development: | Example 1: (from rhyme) Do an example as shown below to demonstrate what each stanza of the rhyme means. Example A: Look at the numbers in the one's column and ask: More on top? 36 No need to stop. -22 14 Example B: Look at the numbers in the one's column and ask: More on the floor? 24 Go next door, -16 Get ten more. 8 Example C: Look at the numbers in the one's column and ask: Numbers the same? 35 Zero's the game. -15 20 Example 2: (Using manupilatives) 1. Place straw and cup manipulative on the overhead. 2. Write the problem on the overhead. 24 -16 3. Lay out two sets of ten straws and four ones to show that there are 24 straws. 4. Show the students that you have ten straws in the first bundle and ten in the second bundle. 5. Now count aloud "ten" (the first bundle), "twenty" (the second bundle),"twenty-one, twenty-two, twenty-three, twenty-four" (the ones). 6. Ask the students if they can take six ones away from four ones.[no] 7. So now take one of the ten bundles and trade it in for ten ones. 8. Show students that they now have ten ones plus four ones. 9. Count the ones aloud, showing that they now have 14 ones on the right side and only one bundle of tens left on the left side. 10. Show students that there are still 24. 11. Now ask the students can they take six ones from fourteen ones.[yes] 12. Six subtracted from fourteen is eight and one subtracted from one is zero. 13. So our answer is eight. 14. On the overhead show the students how when you borrow ten from the tens side you mark through the two and now only have one ten left (now there will be a one in place of the two) Show how you mark through the four and make it fourteen by adding the ten from the tens side.(Students will already be familiar with carrying numbers from their advanced addition with regrouping) 15. Model several examples. |
Practice: | 1. Give each child a set of straw and cup manipulatives. 2. Write problems on the overhead. 3. Have the children to count the straws aloud with you. 4. Call on children to tell you what to do next. |
Accommodations: | 1. Children requiring remediation can practice simple regrouping (e.g. 13-5). OR 2. Work on simple subtraction skills without regrouping (if necessary) AND/OR 3.Have direct one-one instruction by teacher or assitant teacher. OR 4. Children with motor problems may use larger soft blocks as manipulatives, use pre-programmed worksheet on computer illustrating the same concept so the children can use a big mac or other alternative mouse or touch screen if requied. |
Checking For Understanding: | 1.After the independent practice is completed have each children demonstrate and answer at least one problem. 2. Assign short (no more than 10 question) subtraction with regrouping worksheet for homework. Success is measured as 80% accuracy. |
Closure: | 1.Bring the session to a close by having the children orally relate their subtraction problems and their products from the worksheet. 2. Ask the children to look for opportunities to use this new skill at home, for example, while helping someone cook. Tell them they can share this with the class during math time tomorrow. |
Evaluation: | |
Teacher Reflections: |
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