Teaching the Common Core Math Standards With Hands-On Activities, Grades 3-5 (57 page)

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Operations and Algebraic Thinking: 5.OA.2

“Write and interpret numerical expressions.”

2. “Write simple expressions that record calculations with numbers, and interpret numerical expressions without evaluating them.”

Background

Numerical expressions contain numbers and operation symbols. Verbal expressions contain words and phrases. Any mathematical verbal expression can be written as a numerical expression. For example, the expression “subtract 5 from 7 and then multiply by 2” can be written as

Activity: The Expression Game

Working in pairs or groups of three, students will play a game in which they write numerical expressions when given mathematical verbal expressions. Players who write an expression correctly receive a point. The winner is the player who receives the most points at the end of the game.

Materials

Scissors; reproducible, “Expression Game Cards,” for each pair or group of students.

Procedure

1.
Explain that key words may be used to indicate basic mathematical operations:

• Some examples of words that indicate addition include
  add, plus, sum, total
  , and
  in all
  .
  
• Some examples of words that indicate subtraction include
  subtract, minus, difference
  , and
  fewer than
  .
  
• Some examples of words that indicate multiplication include
  multiply, product
  , and
  times
  .
  
• Some examples of words that indicate division include
  divide, quotient
  , and
  half
  .
  

2.
Provide a few examples of how to write numerical expressions based on mathematical verbal expressions, such as the following:

• 3 times the sum of 5 and 2. Answer:
  
• 2 less than 10, divided by 2. Answer:
  
• The sum of 5 and 7 divided by the sum of 4 and 2. Answer:
  

3.
Hand out copies of the reproducible. Explain that it contains 20 cards and that each card has a verbal expression. Students are to cut out the cards, shuffle them, and place them in a pile face down.

4.
Explain the game. Students will take turns flipping a card over. Both (or all three) students are to then write the numerical expression that is equivalent to the verbal expression on the card. Correct expressions are worth one point. If both (or all three) students are correct, they each receive one point. Students with incorrect expressions do not receive any points. To determine who is correct, the students must discuss each expression and agree on the answer. If they cannot, you, serving as the referee, provide the correct answer.

5.
Remind students to pay close attention to key words and the order of operations. Then start the game.

6.
Students may play until time is called or until all the cards have been used.

Closure

Discuss the answers to each card to make sure that the expressions students wrote were correct. Note instances where correct answers varied. Place a few examples on the board and have students share their answers and explain their reasoning.

Answers

Answers may vary slightly; a correct answer for each card follows.
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