Question: Shelly has ten $10 bills and four fewer $5 bills. How much money does Shelly have in all?
Answer with step-by-step thinking: Shelly's ten $10 bills amount to 10 x $10 = $100. She has 10 - 4 = 6 $5 bills. The 6 $5 bills amount to 6 x $5 = $30. Thus, Shelly has $100 + $30 = $130 in all.
So the answer is 130.

Question: A new edition Geometry book has 450 pages which are 230 pages less than twice as many pages as the old edition. How many pages did the old edition Geometry book have?
Answer with step-by-step thinking: Let x be the number of pages of the old edition Geometry book. The new edition Geometry book has 2x - 230 = 450 pages. 2x = 450 + 230. 2x = 680. x = 340 pages.
So the answer is 340.

Question: Jason bought a new bookcase that can hold a maximum of 80 pounds of weight. Jason has 70 hardcover books that each weigh half a pound, 30 textbooks that each weigh 2 pounds, and 3 knick-knacks that each weight 6 pounds. How many pounds over the bookcase's weight limit is this total collection of items?
Answer with step-by-step thinking:
First find the total weight of the hardcover books: 70 books * .5 pound / book = 35 pounds. Then find the total weight of the textbooks: 30 books * 2 pounds / book = 60 pounds. Then find the total weight of the knick - knacks: 3 knick - knacks * 6 pounds / knick - knack = 18 pounds. Then find the total weight of all the items: 35 pounds + 60 pounds + 18 pounds = 113 pounds. Then subtract the bookcase's weight limit: 113 pounds - 80 pounds = 33 pounds.
So the answer is 33.