Come up with a question and reasoning that would justify [5] as the answer.
The question is: Jack orders 3 sandwiches that cost $5 each. He pays with a $20 bill. How much does he get in change?
Reasoning: The cost was 3 * 5 = $15. So he got 20 - 15 = $5 in change.

Come up with a question and reasoning that would justify [40] as the answer.
The question is: A mother planted a 16-inch tree on her son's first birthday. On the day the tree was planted, the boy was 24 inches tall. If the tree grows twice as fast as the boy does, how tall will the tree be by the time the boy is 36 inches tall?
Reasoning: The boy grew 36 - 24 = 12 inches since the tree was planted. Since the tree grows twice as fast as the boy, it will have grown 12 * 2 = 24 inches during this time period. Thus, the final height of the tree is 16 + 24 = 40 inches.

Come up with a question and reasoning that would justify [450] as the answer.
The question is: Lorenzo put three full cans of thumbtacks into his pocket and went off to work at the corkboard factory. It was Lorenzo's job, as head of quality control, to test every cork board for its ability to hold thumbtacks. He placed one thumbtack from each of the three cans of thumbtacks into every board tested. At the end of the day, he had tested 120 boards and had 30 tacks remaining in each of the three cans. What was the total combined number of thumbtacks from the three full cans?
Reasoning: At the end of the day, he had tested 120 boards, each with three tacks, for a total of 3 * 120 = 360 tacks. He had 30 tacks remaining in each of the three cans, for an additional 3 * 30 = 90 thumbs tacks. Therefore, the original total combined number of thumbtacks in the three full cans of thumbtacks was 360 + 90 = 450 thumbtacks.