## Thursday, December 15, 2011

### Divisibility! (If you missed the notes)

Divisible - when a number can be divided by another number, with no remainder.

Divisibility Rules...

Rule for 1
All whole numbers are divisible by 1
e.g. 3÷1=3
111÷1=111

Rule for 2
All even numbers are divisible by 2
Even numbers end in 2,4,6,8,0
Odd numbers end in 1,3,5,7,9

Rule for 3
The sum of the digits is divisible by 3
e.g.1+2+3+6=1+2=3
3 is divisible by 3

Rule for 4
4=2x2
All numbers that are divisible by 2 twice
e.g. 16÷2=8
8÷2=4
Then 16 is divisible by 4

Rule for 5
All numbers  ending in 0 or 5
e.g. 5,10,15,20,25,30,35,40

Rule for 6
If the number is divisible by 2 and 3, then it is divisible by 6.
e.g. 2x3=6

Rule for 7
USE A CALCULATOR!!!!!!!!!!!!
If you find a rule tell Mr. Isfeld and he will publish it ;D

Rule for 8
8=2x2x2
All numbers divisible by 2 three times
e.g. 24÷2=12
12÷2=6
6÷2=3

Rule for 9
The sum of the digits is divisible by 9
e.g. 1+8+9+7+2+3+6= 3+6 = 9
9 is divisible by nine.

Rule for 10
All numbers that end in 0 are divisible by 10
e.g. 10,20,30,40,50,60,70....etc.

Rule for 0
No number is divisible by zero
It is impossible