# Divisibility and factors

A number is considered divisible by another number (divisibility) when the result of the division is an integer and there is no remainder. The number which divides that number is called a factor of that number or its divisor. Division is an operation that is the opposite of multiplying and the property that a number can be divided by another number is called divisibility.
For example: If you divide the number 16 with the number 2, you will get the number 8 as a result and no remainder. That means that the number 16 is divisible by the number 2 and that 2 is a factor of 16. But if you divide the number 16 with the number 3, you will get the number 5 as a result with 1 as the remainder. This means that 16 is not divisible by 3 and 3 is not a factor of 16.

The basic rules that can help you determine whether a number can be divided by another number (and which one) are ilustrated in the picture below. These rules are particularly useful in prime factorization or finding the least common multiple or the greatest common factor.

## Divisibility exams for teachers

 Exam Name File Size Downloads Upload date Positive integers Divisibility of positive integers – very easy 107.1 kB 3836 October 13, 2012 Divisibility of positive integers – easy 157.4 kB 2704 October 13, 2012 Divisibility of positive integers – medium 164.8 kB 3415 October 13, 2012 Divisibility of positive integers – hard 179.1 kB 2625 October 13, 2012 Positive decimals Divisibility of positive decimals – very easy 559.2 kB 1237 October 13, 2012 Divisibility of positive decimals – easy 572.4 kB 1102 October 13, 2012 Divisibility of positive decimals – medium 575.7 kB 1135 October 13, 2012 Divisibility of positive decimals – hard 561.3 kB 1180 October 13, 2012 Positive fractions Divisibility of positive fractions – very easy 119 kB 1211 October 13, 2012 Divisibility of positive fractions – easy 564.6 kB 1065 October 13, 2012 Divisibility of positive fractions – medium 572.1 kB 1178 October 13, 2012 Divisibility of positive fractions – hard 576.9 kB 989 October 13, 2012 Positive mixed numbers Divisibility of positive mixed numbers – easy 568.8 kB 1119 October 13, 2012 Divisibility of positive mixed numbers – medium 583.9 kB 930 October 13, 2012 Divisibility of positive mixed numbers – hard 612.3 kB 940 October 13, 2012 Positive improper fractions Divisibility of positive improper fractions – very easy 170.5 kB 979 October 13, 2012 Divisibility of positive improper fractions – easy 564.5 kB 922 October 13, 2012 Divisibility of positive improper fractions – medium 564.4 kB 878 October 13, 2012 Divisibility of positive improper fractions – hard 574.6 kB 973 October 13, 2012 Divisibility of positive improper fractions – very hard 574.1 kB 865 October 13, 2012 Non positive integers Divisibility of integers – very easy 82.3 kB 1099 October 13, 2012 Divisibility of integers – easy 154.6 kB 1144 October 13, 2012 Divisibility of integers – medium 163.2 kB 1394 October 13, 2012 Divisibility of integers – hard 173.4 kB 1462 October 13, 2012 Non positive decimals Divisibility of decimals – very easy 567.8 kB 993 October 13, 2012 Divisibility of decimals – easy 559.9 kB 1103 October 13, 2012 Divisibility of decimals – medium 557 kB 951 October 13, 2012 Divisibility of decimals – hard 559.6 kB 1254 October 13, 2012 Non positive fractions Divisibility of fractions – very easy 552.2 kB 984 October 13, 2012 Divisibility of fractions – easy 569.2 kB 1032 October 13, 2012 Divisibility of fractions – medium 571.5 kB 937 October 13, 2012 Divisibility of fractions – hard 595.4 kB 1028 October 13, 2012 Non positive mixed numbers Divisibility of mixed numbers – easy 559.7 kB 1014 October 13, 2012 Divisibility of mixed numbers – medium 588.7 kB 982 October 13, 2012 Divisibility of mixed numbers – hard 585.2 kB 880 October 13, 2012 Non positive improper fractions Divisibility of improper fractions – easy 175 kB 1193 October 13, 2012 Divisibility of improper fractions – medium 183.4 kB 1085 October 13, 2012 Divisibility of improper fractions – hard 212.8 kB 1290 October 13, 2012

There are tricks and shortcuts in the process of determination whether a number is divisible by another number.
Every number, including prime numbers, is divisible by the number 1 and itself.
All even numbers (those ending in 0, 2, 4, 6 or 8 ) are divisible by 2.
If you calculate the sum of all the digits in a number and that sum is divisible by 3, then the number is divisible by 3 as well.
A number is divisible by 4 if the last two digits in that number are divisible by 4.
Every number ending in 0 or 5 is divisible by the number 5.
A number is divisible by 6 if it is also divisible by 2 and 3.
If the last three digits in a number are divisible by 8, then that whole number is divisible by 8.
The same rule applies for checking if a number is divisible by the number 9 as it does for number 3. If the sum of all digits in the number is divisible by 9, then the entire number is divisible by 9.
Every number ending in 0 is divisible by the number 10.

## Factoring exams for teachers

 Exam Name File Size Downloads Upload date Factoring all positive factors 119.1 kB 2242 October 13, 2012 Factoring numbers without exponents 125.7 kB 1331 October 13, 2012 Factoring with exponents 129.8 kB 1782 October 13, 2012

## Divisibility and factoring worksheets for students

 Worksheet Name File Size Downloads Upload date Positive Divisibility of positive integers 137.7 kB 1809 October 14, 2012 Divisibility of positive decimals 192.9 kB 1148 October 14, 2012 Divisibility of positive fractions 252.6 kB 956 October 14, 2012 Divisibility of positive mixed numbers 227 kB 907 October 14, 2012 Divisibility of positive improper fractions 248.8 kB 1002 October 14, 2012 Non positive Divisibility of integers 143.7 kB 1207 October 14, 2012 Divisibility of decimals 222.3 kB 984 October 14, 2012 Divisibility of fractions 260.9 kB 1068 October 14, 2012 Divisibility of mixed numbers 276.9 kB 927 October 14, 2012 Divisibility of improper fractions 234.4 kB 1035 October 14, 2012 Factoring numbers Factoring 198.2 kB 1854 October 14, 2012