Do your students struggle with finding the factors of a number to determine prime and composite numbers? Help them master 4.OA.4 CCSS by using this Divisibility Rules Poster Set. Designed to simplify learning for both you and your students, this set covers everything from divisibility rules for numbers 1 through 12 to essential math vocabulary like factors, multiples, prime, composite, and divisible.Included are divisibility rules for 1 through 12 - including some of the more unusual rules for 7