Can't remember the difference between a prime number and a square number? Forgotten how many sides on a pentagon (5), heptagon (7), or nonagon (9)? Then you need DK's new Math Dictionary! Inside, you'll find more than 300 entries on the words, phrases, and concepts used by grade-school students in their math classes and in their lives outside school.

Can't remember the difference between a prime number and a square number? Forgotten how many sides on a pentagon (5), heptagon (7), or nonagon (9)? Then you need DK's new Math Dictionary! Inside, you'll find more than 300 entries on the words, phrases, and concepts used by grade-school students in their math classes and in their lives outside school.