We have a question: Ali is collecting bottle caps. He has 125 bottle caps. He has red ones and green ones. If he has 50 red caps, what percentage of caps are green?
And an answer: 60
So how you got the answer?
He has 75 green caps because 125 - 50 = 75. The proportion of caps that are green is .6 because 75 / 125 = .6. The percentage that are green is 60 because .6 x 100% = 60%.

We have a question: There were 349 pieces of candy in a bowl. Talitha took 108 pieces and Solomon took 153 pieces. How many pieces of candy remain in the bowl?
And an answer: 88
So how you got the answer?
349 - 108 = 241 and 241 - 153 = 88. There are 88 pieces of candy left in the bowl.

We have a question: Jack bought 3 books a month at $20 each. He sells them back at the end of the year for $500. How much money did he lose?
And an answer: 220
So how you got the answer?
He bought 3 * 20 = $60 of books a month. That means he bought 60 * 12 = $720 of books a year. So he lost 720 - 500 = $220.