Question. Mary has 5 green crayons and 8 blue crayons of different shades. If she gives out 3 green crayons and 1 blue crayon to Becky, how many crayons does she have left?
Answer. 9
What step-by-step reasoning justifies that answer?
Reasoning: She had 5 + 8 = 13 crayons to start with. She gave out 3 + 1 = 4 crayons to Becky. She will have 13 - 4 = 9 crayons left.