Divisibility and Exponents

Divistibility Rules~
by 2- its ends in 0,2,4,6,8 for example, 84 is divisible by 2
by 3- if the sum of its digits is divisible by 3 for example, 9/3=3
by 4- if the last 2 digits are divisible by 4 for example,128 7*4=28
by 5- if it ends in 0, or 5 for example, 20 or 25
by 9- if the sum of its digits is divisible by 9 for example, 72/8=9
by 10- if the number ends in a 0 for an example 30

Factors~
10-1,2,5,10
21-1,3,7,21
24-1,2,3,4,6,8,12,24
31-1,31 -this is a prime number
A prime number is 1 and the number itself

Exponents~
Exponents can be used to show repeated multiplacation
3^7=3*3*3*3*3*3*3 3= base 7=exponent
-a power has two parts
-a base has an exponent
-the expression 3^2 is read "three to the second power
(-4)(-4)=8^2