Divisibility Rules

How do you know if a number is divisible by 3?

• If the sum of the digits is a multiple of 3
• If it ends in 3, 6, or 9
• If it is an even number
• If it ends in 0 or 5

All of these numbers are divisible by 5 except for...

• 75,395
• 984,940
• 222,222,235
• 8,943,892

The divisibility rule for 9 is...

• Divide the whole thing by nine
• Add the digits together.  If the sum is divisible by 9, the original number is divisible by 9
• Multiply the digits together by 9
• Add the digits together and then add 9.

Is 525 divisible by 5?

• Yes
• No

Is 848,960 divisible by 10?

• Yes
• No

Is 2,385 divisible by 10?

• Yes
• No

As long as a number is even it can be divided by 2. 

• True 
• False 
• #IDK #IDC
• You better care! 

All even numbers are divisible by 2

• True
• False

All odd numbers are divisible by 3

• True
• False

All even numbers are divisible by 5

• True
• False