A number can be divided by **2**, if the last digit is even: 0, 2, 4, 6, 8.

A number can be divided by **3**, if its cross sum is divisible by 3.

A number can be divided by **4**, if its last two digits are divisible by 4.

A number can be divided by **5**, if its last digit is 0 or 5.

A number can be divided by **6**, if its last digit is even AND its cross sum is divisible by 3.

A number can be divided by **8**, if its last three digits are divisible by 8.

A number can be divided by **9**, if its cross sum is divisible by 9.

A number can be divided by **10**, if its last digit is 0.

A number can be divided by **25**, if its last two digits are divisible by 25, i.e. 00, 25, 50 or 75.

A number can be divided by **100**, if its last two digits are equal to 0.

A number can be divided by **1000**, if its last three digits are equal to 0.

If you would like to have a vivid explanation with a detailed example, please read the page Simplifying/Reducing Fractions - Learn this magic trick!

**Step 1: In what case was a number divisible by 2?**

A number can be divided by **2**, if the last digit is even: 0, 2, 4, 6, 8.

**Step 2: Test, if the number is divisible by 2**

The last digit of 15 is 5. 15 is therefore **not** divisible by 2.