When reducing fractions or finding the factors of a integer it is helpful to know the divisibility rules .
These are the most popular rules you should know.
Divisibility by 2: The last digit of the number is an even integer
Divisibility by 3: The sum the digits of the integer is divisible by 3
Divisibility by 4: The last two digits are divisible by 4
Divisibility by 5: The last digit is "0" or "5"
Divisibility by 6:If the number is divisible by 2 and 3, then it's divisible by 6
Divisibility by 9: The sum of the digits of the integer is divisible by 9