Beacon Lesson Plan Library

Melt in Your Mouth Subtraction

Jennifer Slichter
Santa Rosa District Schools

Description

The lesson involves role-play and using manipulatives to solve subtraction problems.

Objectives

The student demonstrates an awareness of addition and subtraction in everyday activities (using concrete objects, models, drawings, role playing).

Materials

-Dry erase or chalk board
-10 large construction paper cut-outs in bright candy colors
-1 set of Subtraction flashcards
-1 plastic plate per student and one for teacher
-Sentence strip that reads, -Subtraction is an act of taking away from a set to form a new set.-
-Melt in Your Mouth Subtraction worksheet - 1 for each student (See Attached File).
-Connecting cubes - 10 cubes per student and one set for teacher
-Snack packs of candy-coated chocolate pieces - one per student
-Candy-coated chocolate pieces- five per student

Preparations

1. Prepare materials.
2. Write the word 'Subtraction' on the board.
3. Make copies of the Subtraction Worksheet for each student (See Attached File).

Procedures

Note: This lesson primarily deals with using manipulatives to solve subtraction problems.

1. Introduce lesson by holding up 5 construction paper cut outs that resemble candy. Ask class what the cut outs look like. Get responses. Tell class that the cut outs represent chocolate candy pieces and that we are going to use real candy pieces for our lesson later.

2. Put the "candy" cut outs on a large plastic plate and hold in front of the room. Count how many in all (5). Ask class what would happen if the candy was real and someone ate one of them. Would we have more or less? Are we taking away or adding if someone ate one? Point to the word subtraction written on the board. Read the word together as a class. Then point to the sentence strip that is on the board that reads, "Subtraction is the act of taking away from a set to form a new set." Explain that when we subtract we take away and then count how many we have left.

3. Review concept of addition. Tell class that we are going to review addition. Put two large "candy" cut outs on the plate. Ask students how many "candy" cut outs there are on the plate. Write two on the board. Then, put three more large "candy" cut outs on the plate. Ask students how many more we put on the plate. Write three on the board. Ask students how many in all. Write the addition sentence, 2 + 3 = 5 on the board. Ask class if we added to the candy or took away. Remind class that addition is the act of combining two sets to form a new set.

4. Role-play concept of subtraction by calling on volunteers to come to the front of the room. Students will pretend that they are going to eat candy off the plate. The student volunteer counts how many "candy" cut outs he has on the plate in the beginning and tells the class. Then he takes some off and tells the class how many. Then he counts how many he has left. Teacher models how to write the subtraction sentence on the board. Explain that the first number is the number we begin with, the second number is the number we take away and the answer or last number is the number we have left. Repeat this activity with several volunteers.

5. Give examples and non-examples of subtraction problems. Students stand if the example is a subtraction problem and will sit if the example is an addition problem. Example: I had two pieces of candy and my Mom gave me two more. How many do I have now? (Students should remain seated). I have three pieces of candy and I eat one. How many do I have left? (Students should stand). Vary with speed and repeat with several examples.

6. Tell class that the next activity will involve a game. Draw a large tic-tac-toe board on the board. Tell class that Xs will be boys and Os will be girls. Volunteers will be called to solve the subtraction problems and if they get them right they will mark the board with an X or 0 for their team. Tell the class that they may draw circles or sticks on the board to solve the answer. Model an example to the class. Draw five circles on the board and take one away. Count how many are left. Remind the class that the subtraction problem would be 5-1=4. Remind the class that means 5 take away 1 equals 4. Call on volunteers to solve these subtraction problems 5-1=4,5-2=3, 5-3=2, 5-1=4, 5-5=0. Play activity until there is a winner. Repeat if desired.

7. Pass out paper plates to the class (one per each student). Pass out 5 chocolate candy pieces to each student and have them place on plate. Ask class to count how many in all. Ask class to put one candy in their mouth and count how many are left. Write the subtraction sentence 5-1=4 on the board. Ask class to count how many pieces of candy they have left on their plate now. When students have counted four, ask the class to eat one piece of candy and to count how many they have left on the plate now. Write the subtraction sentence 4-1=3 on the board. Ask students eat one piece of candy and to count how many they have left. Get responses and write the subtraction sentence 3-1=2 on the board. Ask students to eat one piece of candy and to count how many they have left. Get responses and write the subtraction sentence 2-1=1 on the board. Ask students to eat one piece of candy and to count how many they have left. Get responses and write 1-1=0.

8. Divide the class into two teams to play subtraction relay. Take out subtraction flashcards. Tell the class that I am going to hold up a subtraction flashcard and that the first two students on teams 1 and 2 will say the answer. The first student who says the correct answer will get a point for their row. When one of the first two students have given a correct response they both go to the back of the line and the next two students have a turn. Play until everyone has had a turn at the game.

9. Remind the class what they learned about subtraction. We take away from a set when we subtract to find out how many we have left.

10. Pass out the Melt in Your Mouth Subtraction worksheet to the class and read the directions with the students.

11. Pass out connecting cubes to the class. Tell the class the cubes may be used as a manipulative.

12. Students will complete the worksheet on their own using the cubes as a manipulative (See Attached File). Model how to use the cubes and do one problem together.

13. Circulate and assist students as needed.

14. When students have completed the two page worksheet, volunteers will come to the front of the room to write and solve the subtraction problems on the board. The students may also share the writing part of the worksheet with the class.

Assessments

Note: This lesson focuses on subtracting whole numbers. This is a formative assessment using manipulatives to solve subtraction problems. Students will demonstrate the ability to solve subtraction problems using manipulatives and will write answers on the Melt in Your Mouth Subtraction worksheet. Class discussion of answers and teacher modeling of answers will allow students to self assess. Appropriate feedback will be provided to all students. Students who miss two or more answers will be given more instruction and an opportunity to do the worksheet again.

Extensions

If any students have health concerns such as allergies or diabetes, the lesson should be modified to use construction paper cutouts instead of real candy.
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