This book from the founder of Bedtime Math (www.bedtimemath.org) answers math questions covering a multitude of topics. It is quite helpful that the questions are organized by general topics: animals, nature, food, everyday life, Earth and space, and mental math. Some questions answered include: the number of bees needed to make a jar of honey, how fast the fastest growing tree on Earth actually grows, how many gallons of water are needed to put out a fire, and how many soccer balls would fit inside Earth. All of the math is broken down, with explanations for where those numbers came from, so it is all easy to understand. Have your child come up with their own questions and try to answer them (perhaps with some research help from you).