Divisibility
Prime Numbers
Greatest Common Factor
Least Common Multiple
DIVISIBILITY
Number
Rule of divisibility
1
All whole numbers are divisible by 1.
2
All non-zero numbers with a ones digit of 0, 2, 4, 6, or 8 are divisible by 2.
3
If the sum of a number's digits are divisible by 3, then it is divisible by 3. For example, 222 has digits add to 6, so the whole number is divisible by 3 (222/3= 74).
4
A number is divisible by 4 if its last two digits are divisible by 4. For example, 60,548 is divisible by 4, but 6,250 is not.
5
A non-zero number is divisible by 5 if it ends in 0 or 5.
6
A number is divisible by 6 if it is even (divisible by 2) and also divisible by 3. Any even number divisible by 3 is also divisible by 6.
9
Add the digits. If that sum is divisible by nine, then the original number is as well.
For example, 1,044 (1044/9 =116) is divisible by 9 (because 1 + 0 + 4 + 4 = 9).
10
A non-zero number is divisible by 10 if it ends in 0.
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