Divisibility Rules

1. Divisibility Rules Making friends with fractions

2. The rule for “2” 2 goes into every even number….. Even numbers are numbers that end in 0, 2, 4, 6, or 8

3. The rule for “3” 3 will go into a number if 3 goes into the sum of the digits Example: 1,266 The sum of the digits is 1 + 2 + 6 + 6 = 15 3 goes into 15….so 3 goes into 1,266

4. The rule for “4” If 4 goes into the last two digits it goes into the number Example: 240…..4 goes into 40 so 4 goes into 240

5. The rule for “5” 5 goes into any number that ends in “0” or “5”

6. The rule for “6” If 2 and 3 go into a number, so does 6 Example: 132….2 goes into it because it is even….3 goes into it because the sum of the digits is 6….6 goes into it because 2 and 3 do

7. The rule for “7” Take the last digit and double it….subtract that from the remaining digits…continue until you get a number that is divisible by 7 Example: 133…take the last digit and double it…..3 x 2 = 6 13 – 6 = 7….7 goes into 7 so 7 goes into 133.

8. The rule for “8” Not on our list, because it’s a rotten rule! If 8 goes into the last 3 digits, it goes into the number.

9. The rule for “9” Same as the rule for 3…..if 9 goes into the sum of the digits it goes into the number. Example: 1,233….the sum of the digits is 9…9 goes into 9 so 9 goes into 1,233

10. The rule for “10” 10 goes into any number that ends in 0

11. What will divide evenly into: • 222 • 224 • 1,200 • 7,011 • 156 • 440 • 812