Divisibility Rules Sample Problems

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Here are some tips for Divisibility Rules, which aligns with California state standards:

Divisibility Rules

In this topic, you must list all of the factors of a number. To succeed, you must be good at your divisibility rules.

Here are some divisibility rules that should help:
Divisibility by 2: If the number ends in 0,2,4,6, or 8, it is divisible by 2.
Divisibility by 3: If the sum of the digits is divisible by 3, the number is divisible by 3.  
   Example: 27 is divisible by 3 because 2 + 7 = 9, which is divisible by 3.
Divisibility by 4: If the last two digits are divisible by 4.
Divisibility by 5: If the number ends in 0 or 5, it is divisible by 5.
Divisibility by 6: If the number is divisible by 2 and 3.
Divisibility by 9: If the sum of the digits is divisible by 9.
Divisibility by 10: If the last digit is 0.

Example: Factor 18:
Everything is divisible by 1, giving us the factors 1 and 18
18 is divisible by 2, giving us 2 and 9
18 is divisible by 3, giving us 3 and 6
Answer: 1 2 3 6 9 18