Question

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

Step 1: Create Equation: 12+15+x=55

Step 2: Solve it: you will get x=28

Step 3: You could check it by plugging your answer in.

Hope that helps!!!

Answer 2

Answer is A:

Check that the sum of the final answer, 12, and 15 is 55.

this makes sense b/c there must be 28 marbles (55 - 12 - 15 = 28) so 28 + 15 + 12 must = 55.