At a certain bookstore, the best-selling book, "TOP," costs $8. The least-selling book, "ABC," costs $23. Thirteen "TOP" books and four "ABC" books were sold last week. What is the difference in the bookstore's earnings on these two books last week?
Let's think: On "TOP" books the bookstore made 13 * 8 = $104. The "ABC" books, on the other hand, were sold for a total of 4 * 23 = $92. The difference between earnings from these two books is 104 - 92 = $12.. The answer is: 12.

Jan buys 1000 feet of cable. She splits it up into 25-foot sections. She gives 1/4 of that to a friend. She then puts half of the rest in storage. How much does she keep on hand?
Let's think: She gets 1000 / 25 = 40 sections. She gives away 40 / 4 = 10 sections. So she keeps 40 - 10 = 30 sections. She keeps 30 / 2 = 15 sections on hand.. The answer is: 15.

The hobby store normally sells 21,122 trading cards per month. In June, the hobby store sold 3,922 more trading cards than normal. If the hobby store sold the regular number of trading cards in July, how many trading cards did the hobby store sell in June and July combined?
Let's think: In June the hobby store sold 21,122 + 3,922 = 25,044 trading cards. Over June and July the store sold 25,044 + 21,122 = 46,166 trading cards.. The answer is: 46166.

Suzanna's history textbook has 160 pages and her geography textbook has 70 more pages. Her math textbook has half of the sum of the first two books' pages, and her science textbook has twice the number of pages of her history textbook. If Suzanna stacks all her textbooks on her desk, how many pages would there be in total?
Let's think:
Her geography textbook has 160 + 70 = 230 pages. The sum of pages of her history and geography textbook is 160 + 230 = 390 pages. Her math textbook has 390 / 2 = 195 pages. Her science textbook has 160 x 2 = 320 pages. In total, there would be 160 + 230 + 195 + 320 = 905 pages.. The answer is: 905.