Number Properties: Divisibility Flashcards Preview

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Flashcards in Number Properties: Divisibility Deck (11)
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1

Divisible by 2

Units digit is even: {0, 2, 4, 6, 8}.

2

Divisible by 9

Sum of digits is divisible by 9.

3

Divisible by 3

Sum of digits is divisible by 3.

4

Divisible by 4

2-digit number at the end is divisible by 4. Alternatively, X is a number made up of digits a...bc. If the last 2 digits of the number, bc, mod 4 = 0, then X is divisible by 4. If b is odd, then X is divisible by 4 if c is 2 or 6. If b is even, then X is divisible by 4 if c is 0, 4, or 8.

5

Divisible by 10

Units digit is zero (0).

6

Divisible by 6

The number is divisible by 2 (even) and by 3.

7

Divisible by 5

Units digit is zero (0) or 5.

8

Divisible by 7

X is a number made up of digits a...bc. If (a...b - 2*c) mod 7 = 0 then X is divisible by 7. This process can be applied recursively.

9

Divisible by 8

X is a number made up of digits a...bcd. If the last 3 digits of the number, bcd, mod 8 = 0, then X is divisible by 8. If b is even then, X is divisible by 8 if cd mod 8 = 0. If b is odd then, X is divisible by 8 if (cd - 4) mod 8 = 0.

10

Divisible by 11

Alternating difference/sum is divisible by 11. Alternatively, X is a number made up of digits abcd. If (((a - b) + c) - d) mod 11 = 0, then X is divisible by 11.

11

Divisible by 12

The number is divisible both by 3 and by 4.