Butterflies

Enjoy learning about Math while reading about Fred and his quirky tales of Life with the Life of Fred books.
Butterflies is the second book of 10 in the Life of Fred Elementary series.
Life of Fred is a series of math books that break of the old pattern of drill and kill. Instead of nothing but dry exposition and endless drill exercises, they contain fun stories about Fred Gauss, a child prodigy math genius. During his hilarious adventures, he encounters situations that call for solving math problems. Children actually want to read these books.
After each chapter there are "your turn to play" sections where your child gets to practice with pen and paper, what they have just read about. Solutions are given over the page. 

These books are all hardcover, not consumable workbooks which are beautifully presented enabling them to be read again and again.