Meagan Latham - Subtraction Lesson Plan

Lesson Plans

LESSON PLAN FOR SECOND GRADE

Subtraction

· written by: Meagan Latham

· graphics, editing, & formatting by: Dr. Beth McCulloch Vinson

Subject: Introduction to Two-Digit Subtraction with Regrouping

Grade: Two

I. Behavorial Objective:

After a teacher-directed math lesson, the students of Ms. Latham's second-grade class 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%.

II. Instuction/Method:

A. Anticipatory Set:

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. Read and sing the book, The Skip Count Song to refresh students on skip

counting.

4. Use the abacus to refresh the children on skip counting and addition.

5. Express the importance of finding the difference in everyday life, such as

cooking, business, and carpentry.

6. Write the number 16 on the overhead. Show the students the ones place by

pointing to the six. Now the tens place by pointing to the one.

7. Under the 16 subtract 7 so that it looks like this: 16

- 7

B. Statement of Objective:

"When we finish today, you will be able to demonstrate how to regroup

two-digit numbers by borrowing from the tens place."

C. Instructional Input:

1. On the overhead projector construct 16 with a ten strip and six ones.

2. Count it aloud as "ten" (the ten strip), "eleven, twelve, thirteen, fourteen, fifteen

sixteen" (the ones).

3. Ask the students if they can take seven ones away from six ones.[no]

4. Tell them you can not take seven ones away from six ones so, today you are

going to show them what you do in order to solve this problem.

5. Now take the ten strip and trade it for ten ones.

6. Place the ten ones in the row with the six ones.

7. Count all of the ones aloud so that students can see that they still have 16.

8. Now take seven away from the sixteen ones.

9. Show that there are nine ones left.

10. Repeat this process with several problems to make sure students understand.

11. Ask them to help you count aloud.

D. Modeling:

1. Place straw and cup manipulative on the overhead.

2. Write another 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)

Example: 24

- 16

15. Model this example several times.

E. Checking for Understanding:

1. After sharing examples with the children ask them do they have any questions.

2. Make sure they are understanding the process.

3. Quiz the children on their responses and the reason for those responses.

F. Guided 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.

G. Independent Practice:

1. Place the students into groups of four.

2. Give each child in each group a worksheet containing several problems to solve.

3. Instruct the children to work together using their straws and cups to solve the

problem.

4. Tell the children to write their answers on their worksheets.

5. Oversee this activity in case anyone needs help.

1. Strategies to use with Exceptional Children:

a. For enrichment, increase the number of problems given to the gifted

children.

b. For remediation, children will be allowed to practice the very simple

subtraction problems. Ex. 13

- 5

2. Activities which Value Cultural Diversity:

Children who speak English as a second language will count aloud in

their primary language.

3. Activities which Foster Active Inquiry, Critical Thinking, and Problem Solving:

a. The class will take a mini-field trip to the lunchroom to see the many

practical applications of finding the difference using regrouping.

b. Ask the children to go home and ask their friends and family if they

know any situations where finding the difference using regrouping might be needed.

H. Closure and Summary:

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.

III. Assessment Techniques:

The students in Ms. Latham's 2nd-grade class will find the sum and the difference in order to

solve simple addition and subtraction problems at an accuracy rate of at least 90%.

It must be determined whether a child understands the concept of finding the sum, finding the difference,

and skip counting by tens as prerequisite skills. In order to determine whether a child can skip count and

do addition, the teacher could use the abacus to quiz the children. In order to conclude whether the

children understand simple subtraction, the teacher could use ones on the overhead and listen to responses

to determine their understanding of finding the difference.

IV. 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).

Book: Williams, R.L. (1995). The Skip Count Song. Cypress, CA: Creative Teaching

Press. (ISBN: 1-916119-99-8)

Name:___________________________________

2-Digit Subtraction: regrouping

Step 1: Regroup Step 2: subtract the ones Step 3: subtract the tens

Example: 26 Check your answer: 19

- 19 + 17

(1.) 12 (2.) 16 (3.) 18 (4.) 17 (5.) 11 (6.) 15

- 5 - 8 - 9 - 8 - 6 - 7

6. 24 7. 21 8. 27 9. 27 10. 29

- 16 - 18 - 19 - 15 - 17

_____________________________________________________

Use this space to check your answers.

Also, see the Subtraction PowerPoint Slides Shows at:

http://www.athens.edu/pt3/vinson/subtraction.ppt

http://www.athens.edu/pt3/vinson/subtraction_r.ppt