Math for Smarty Pants and The I Hate Mathematics! Book, by Marilyn Burns
Full of experiments and puzzles, these two books are part of the Brown Paper Schoolbook series, meant for kids to have fun learning academic subjects on their own.

The Number Devil, by Hans Magnus Enzensberger
The Number Devil visits Robert in his dreams, and gets him thinking about the strangest things! Rutabaga numbers and prima donnas (roots and primes) are just the beginning. Anyone who’d like a gentle introduction to lots of interesting math topics will enjoy this one.

Hannah, Divided, by Adele Griffin Hannah has a special gift for numbers. This sweet, simple story, set in the 1930’s, shows us the world from the point of view of a girl whose eccentricities aren’t noticed much, until she goes to the big city to learn more math.

Carry On, Mr. Bowditch, by Jean Lee Latham
This is a fictionalized account of the life of Nathaniel Bowditch, who loved math but had to leave school when his family needed his help. He was indentured to a ship chandlery for nine years. Although that dashed his hopes of someday going to Harvard to study math, it was the right place to learn the mathematics behind navigation. When he finally went to sea, he invented a new way to “do a lunar,” and spent endless hours correcting errors in the tables used for navigation. Bowditch’s book, American Practical Navigator, first published in 1902, is still regularly updated, and is carried on U.S. naval vessels to this day.

Powers of Ten, by Philip and Phylis Morrison
The first photo shows a couple having a picnic. It’s shot from one meter above them. The next is from 10 meters, then 100. After we’ve traveled to the edge of the universe, we come back to the couple and zoom in, down past the sizes of atoms and electrons. Each page has one large photo, and explanatory text about what can be seen at that level.

How to Count Like a Martian, by Glory St. John
A really good way to understand place value is to work with other number bases. This is a detective story in which the history of other number systems plays a starring role. “Out of the depths of the dark and starry night come the first of the faint and mysterious sounds.” You have just received a message from Mars. The one kind of language that both Martians and Earthlings would understand is numbers. And so you research the number systems that have been used on Earth, hoping that will help you decipher this message. The book proceeds to explain eight different counting systems, including the abacus and the binary numbers of computers. In the process, the concepts of place value (she just calls it place), base, and zero are explored. By the end of the book, you can see that the beeps and bee-beeps of the message you received are just the counting numbers, Martian style.

The Man Who Counted, by Malba Tahan
Written in Brazil, set in the Middle East, these stories follow the adventures of Beremiz, an accomplished mathematical problem-solver. He uses math to settle disputes, solve riddles and mysteries, and entertain his hosts. I loved how it felt like a mathematical version of Arabian Nights.

Math Without Words, by James Tanton
All ages will enjoy the puzzles in this book, which include illustrations of negative numbers, algebra, and more.