Who knew the sum of a number's digits gives such interesting information? The 18th installment of a 21-part module has scholars investigate division by three and nine. After looking at several examples, they develop divisibility tests...

Students inspect divisibility rules. In this divisibility rules lesson, students study the relationship between factorization and the divisibility rules for 2, 3, 5, 6, 9, and 10. Students read One Hundred Hungry Ants and A Remainder of...