Divisibility Rules
The following set of rules can help you save time in trying to check the divisibility of numbers.
A number is divisible by
|
if
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|---|---|
2
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it ends in 0, 2, 4, 6, or 8
|
3
|
the sum of its digits is divisible by 3
|
4
|
the number formed by the last two digits is divisible by 4
|
5
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it ends in 0 or 5
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6
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it is divisible by 2 and 3 (use the rules for both)
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7
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(no simple rule)
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8
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the number formed by the last three digits is divisible by 8
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9
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the sum of its digits is divisible by 9
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Example 1
- Is 126 divisible by 3? Sum of digits = 9. Because 9 is divisible by 3, then 126 is divisible by 3.
- Is 1,648 divisible by 4? Because 48 is divisible by 4, then 1,648 is divisible by 4.
- Is 186 divisible by 6? Because 186 ends in 6, it is divisible by 2. Sum of digits = 15. Because 15 is divisible by 3, 186 is divisible by 3. 186 is divisible by 2 and 3; therefore, it is divisible by 6.
- Is 2,488 divisible by 8? Because 488 is divisible by 8, then 2,488 is divisible by 8.
- Is 2,853 divisible by 9? Sum of digits = 18. Because 18 is divisible by 9, then 2,853 is divisible by 9.
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