## Tuesday, December 13, 2011

### Divisibility Rules

Divisibility Rules
#1: All whole numbers are divisible by 1
#2: All numbers that end in 0,2,4,6,8 are divisible by 2
#3:All sums of the digits is divisible by 3
#4: All numbers that can be divided in 2 twice are divisible by 4
#5: All numbers that end in 0 or 5 are divisible by 5
#6: All numbers that are divisible by 2 and 3 are divisible by 6
#8: All numbers that can be divided in 2 thrice are divisible by 8
#9: All sums of the digits are divisible by 9
#10: All numbers that end in 0 are divisible by 10

Example for #1: Whole numbers, no decimals.

Example for #2: The last number has to end in an even number.

Example for #3: e.g. 9+8+3+1+4+2=2+7=9 =983142 is divisibile by 3.

Example for #4: Cut the number in half 2 times. e.g. 200 divided by 2=100 divided by 2=50Yes! = 200 is divisible by 4.

Example for #5: 12345 is divisible by 5 because the last number is 5. 1234567890 is divisible by 5 because the last number is 0. 54321 is not divisible by 5 because the last number isn't 5 or 0.

Example for 6: e.g 6+3+9+6+3+9+6=4+2=6, so 6396396 is divisible by by 6.

Example for #8: Cut the number in half 3 times. e.g. 400 divided in 2=200 divided in 2 =100 divided in 2= 50Yes! = 400 is divisible by 8.

Example for 9: e.g. 1+8+9+7+2+3+6=3+6=9 = 9 is divisible by 9.

Example for 10: 12340 is divisible by 10 because the last number is 0. 12345 is not divisible by 10 because the last number isn't 0.