Divisibility Rules

The following set of rules can help you save time in trying to check the divisibility of numbers. Instead of actually dividing into the numbers, try the rules in Table 1.

Example 1

Answer the following.

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Is 126 divisible by 3?

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Sum of digits of 126 = 9. Since 9 is divisible by 3, 126 is divisible by 3.

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Is 1,648 divisible by 4?

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48 is divisible by 4, so 1,648 is divisible by 4.

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Is 186 divisible by 6?

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186 ends in 6, so it is divisible by 2. Sum of digits = 15.

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5 is divisible by 3, so 186 is divisible by 3. 186 is divisible by 2 and 3; therefore, it is divisible by 6.

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Is 2,488 divisible by 8?

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488 is divisible by 8, so 2,488 is divisible by 8.

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Is 2,853 divisible by 9?

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Sum of digits of 2,853 = 18. 18 is divisible by 9, so 2,853 is divisible by 9.

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4,620 is divisible by which of the following numbers?

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2, 3, 4, 5, 6, 7, 8, 9.