6th Grade Math Textbook, Progress

31

Stephanie and Alexandria made a survey about

pet ownership. Their survey shows that a group of

sixth graders owns 56 pets: 12 dogs, 13 cats, and

the rest birds. How many of the pets are birds?

Substitute 31 for nin the equation

to test whether the equation is true.

n
 25  56

31 
 25 56 The answer checks.

Visualize yourself in the problem above as

you reread it. List the facts and the question.

Strategy: Write an Equation

n
 25  56 n
 25 56 and

Try 30. 30
 25  55 n 56  25

Try 31. 31 
 25  56 n 31

There are 31 birds.

Dog 12

Cat 13

56

Bird ??

Animal Tally Total

Pet Survey

Let n

represent

the number

of birds.

addition

equation

or

addition

sentence

Facts: 56 pets

12 dogs

13 cats

The rest are birds.

Question:How many pets are birds?

Use the information to write an equation.

Write words first.

Number 
 Number  Total

of of dogs number

birds and cats of pets

n 
 12 
 13  56

n 
 25  56

You can solve the equation by the Guess and Test

strategy or by using a related subtraction sentence.

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