Curriculum › Math ›Grade 4

Grade 4 Math · Level 2, Multiplication, Division & Factors

Divisibility Rules

How the lesson starts: Divisibility Rules

1. Detective Dot's clues

   Hello, junior detective! Detective Dot cracks number cases fast. Is 7,236 divisible by 4? Dot never does long division. She hunts for clues in the last digits! Let's learn her tricks.

2. Last-digit clues

   Clue one: peek at the last digit. For 2, it's even: 0, 2, 4, 6 or 8, like 358. For 5, it ends in 0 or 5, like 745. For 10, it ends in 0, like 910.

3. Last-two-digit clues

   Clue two: for 4, look at the last two digits. 7,236 ends in 36, and 36 = 4 × 9. So 4 fits 7,236! For 25, the last two digits are 00, 25, 50 or 75. For 100, they are 00.