We have a question: Nicky is trading baseball cards with Jill. If Nicky trades two cards worth $8 each for 1 card worth $21, how many dollars of profit does he make?
And an answer: 5
So how you got the answer?
First find the total cost of the two $8 cards: $8 / card * 2 cards = $16. Then subtract the cost of the cards Nicky gave away from the cost of the card he received to find his profit: $21 - $16 = $5.

We have a question: It takes 7 years for an apple tree to bear fruit. If Lydia planted a tree when she was 4 years old and is now 9 years old, how old would she be when she gets to eat an apple from her tree for the first time?
And an answer: 11
So how you got the answer?
The tree has been planted for 9 - 4 = 5 years. It will take another 7 - 5 = 2 years for it to bear fruit. Lydia will be 9 + 2 = 11 years old.

We have a question: The math questions in a contest are divided into three rounds: easy, average, and hard. There are corresponding points given for each round. That is 2, 3, and 5 points for every correct answer in the easy, average, and hard rounds, respectively. Suppose Kim got 6 correct answers in the easy; 2 correct answers in the average; and 4 correct answers in the difficult round, what are her total points in the contest?
And an answer: 38
So how you got the answer?
Kim got 6 points / round x 2 round = 12 points in the easy round. She got 2 points / round x 3 rounds = 6 points in the average round. She got 4 points / round x 5 rounds = 20 points in the difficult round. So her total points is 12 points + 6 points + 20 points = 38 points.