Divisibility Rules One number is divisible by another

Divisibility Rules One number is divisible by another number when it can divide into it without a remainder. Ex. 56 is divisible by 7 because it goes into 56 exactly 8 times.

§ The following number is divisible by (2, 3, 5, 6, 9, 10). Why? What do you think are the rules? § 492, 570

Rule for 2. . . A number is divisible by 2 if the last digit (ones place) is an even number (0, 2, 4, 6, 8) Ex. 3, 978 Not an example: 4, 975

Rule for 3. . . A number is divisible by 3 if the sum of the digits is divisible by 3. Ex. 315 b/c 3 + 1 + 5 = 9 and 3 goes into 9 Not an example: 139 b/c 1 + 3 + 9 = 13 and 3 does not go into 13

Rule for 4. . . A number is divisible by 4 if the last two digits form a number divisible by 4. Ex. 8, 512 12 makes up the last two digits and 4 goes into 12 Not an example: 7, 518 into 18 4 does not go

Rule for 5. . . A number is divisible by 5 if the last digit (ones place) is a 0 or 5. Ex. 14, 975 Not an example: 10, 978

Rule for 6. . . A number is divisible by 6 if the number is divisible by BOTH 2 and 3. Ex. 48 is divisible by 2 and 3 so it is divisible by 6 Not an example: 20 is divisible by 2 but not 3 so it’s not divisible by 6

Rule for 8. . . A number is divisible by 8 if the last three digits is divisible by 8. Ex. 2848 is divisible by 8 b/c 848 is divisible by 8 Not an example: 32, 850 is not divisible by 8 b/c 8 does not go into 850

Rule for 9. . . A number is divisible by 9 if the sum of the digits is divisible by 9. Ex. 711 b/c 7 + 1 = 9 and 9 goes into 9 Not an example: 93 b/c 9 + 3 = 12 and 9 does not go into 12