A quick way to estimate the sum of two numbers is to round each number and
then add the rounded numbers. It is likely that this won't be the exact answer but it
may be close enough for some purposes.

How to Estimate a sum by rounding.

- Round each term that will be added
- Add the rounded numbers

Some uses of rounding are:

- Checking to see if you have about enough money to buy what you want.
- Getting a rough idea of the correct answer to a problem.