Amazon.com description: Product Description: The book of "A Handbook of Calculating 24" includes 1,362 math questions. In each question, you will be given 4 numbers ranging from 1 to 13, using which you will try to find out how to calculate 24 using the operations of addition, subtraction, multiplication, and division. You could use this book to: 1. Help your kids improve math skills, and become math confident in school 2. Spend time working together with your family members and have lot of fun 3. Stay with your friends and enjoy fun time together 4. Act as a brain teaser while riding on the train or flying a long trip somewhere Get this book and have some fun!