Question

Read the word problem below.

Antonio has a total of 55 marbles. He has 15 green marbles and 12 red marbles. The rest of the marbles are blue. How many blue marbles does he have?

A student solves this problem by writing an equation. Which strategy could help check the student’s answer?

Answer 1

he has 28 blue marbles 15+12-55=28

Answer 2

There are 28 blue marbles.

Explanation:

Antonio has 15 green marbles and 12 red marbles. The rest of the marbles are blue.

Let the number of blue marbles be x

Total marbles green plus red =
`15+12=27`

Now, Antonio has a total of 55 marbles.

Equation forms:

`55=x+27`

We will subtract 27 from 55 to get x.

=
`55-27=x`

Hence x = 28

Therefore, there are 28 blue marbles.