There are 336 books in a library. On Monday, 124 books are taken out. On Tuesday, 22 books are brought back. How many books are there now? Give the rationale and then the answer.
Let's think step by step. At the end of Monday, there are 336 - 124 = 212 books left. At the end of Tuesday, there are 212 + 22 = 234 books.. The answer is: 234.

Jackson and Brandon both invest $500 in the stock market. Jackson's investment quadruples in value, while Brandon's is reduced to 20% of the initial value. How much more money does Jackson have than Brandon now? Give the rationale and then the answer.
Let's think step by step. First find the end value of Jackson's investment: $500 * 4 = $2000. Then find the end value of Brandon's investment: 20% * $500 = $100. Then subtract the value of Brandon's investment from the value of Jackson's investment to find the difference: $2000 - $100 = $1900.. The answer is: 1900.

Carl wants to buy a new coat that is quite expensive. He saved $25 each week for 6 weeks. On the seventh week, he had to use a third of his saving to pay some bills. On the eighth week, his dad gave him some extra money for him to buy his dream coat. If the coat cost $170, how much money did his dad give him? Give the rationale and then the answer.
Let's think step by step. Carl saved in 6 weeks $25 / week x 6 weeks = $150. On the seventh week, he ended up having to pay in bills $150 / 3 = $50. His savings were then $150 - $50 = $100. His dad gave him $170 – $100 = $70.. The answer is: 70.