You know several methods of subtraction which are:

- Mental Subtraction
- Paper and Pencil
- Calculator

You should choose the method that is easiest, fastest and most accurate. It is very valuable
to become proficient in all methods. A calculator is easiest but often not the
fastest way to subtract. Mental math is the fastest method but not always the easiest.
Using paper and pencil is necessary on complex problems that require an exact
answer.

### Subtracting Numbers with a calculator

Subtracting numbers (for example 68 - 45 ) with a calculator involves several steps.