## Goldfish Subtraction

### Sheila Spiddle

#### Description

Students explore subtraction and number sentences using Goldfish crackers.

#### Objectives

The student writes number sentences for given situations involving the addition, subtraction, multiplication, and division of whole numbers.

#### Materials

-Dixie cups, one for each student
-Goldfish crackers, 10 for each student
-Pencil & blank paper, one for each student
-Clipboard, one for each student
-Book: Wise, William. [Ten Sly Piranhas]. New York: Scholastic Inc., 1993.

#### Preparations

1. Gather all materials and place a sheet of blank paper on each clipboard along with a pencil at each student's seat.
2. Have 10 Goldfish crackers already counted out and placed in each cup at each student's seat.
3. Locate and preview the book [Ten Sly Piranhas].

#### Procedures

1. Review the students' prior knowledge on subtraction. Model some simple subtraction sentences on the board or on an overhead chart. Have the students fill in the answers.

2. Have the students sitting on the floor. Read aloud the story [Ten Sly Piranhas] by William Wise (a counting story in reverse).

3. Direct students back to their seats to get their clipboards with paper, pencil, and Dixie cups of 10 Goldfish crackers. Have students bring their materials back to the floor.

4. To gain the students' interest in this lesson, tell them they now are going to be the piranhas swimming in the river.

5. Read the story aloud again and tell the students that they are to write the number sentence they hear, and then eat the designated amount of Goldfish crackers to solve the problem.

6. Model the first subtraction sentence in the story on the board or overhead chart. Allow students to eat the cracker(s).

7. Then read each page and pause, giving students time to write the subtraction sentence and answer. Allow time to create the sentence using the crackers.

8. After students have written the second subtraction sentence, circulate to make sure everyone understands. Offer individual feedback or write the sentence on the board and conduct an open discussion. If several students are having problems, monitor the writing of the third subtraction sentence. Continue doing this until the end of the story. Students should be able to write the last few subtraction sentences by themselves.

#### Assessments

NOTE: This lesson only teaches and assesses subtraction.

Assess individual student understanding of subtraction sentences by reviewing the list of subtraction problems written down that coincide with the story [Ten Sly Piranhas] by William Wise. Provide individual feedback to those who are still having difficulty.

#### Extensions

Modification: Have the subtraction problems already written down on paper so the student would only have to write the answer as the story is being read.