A quick way to estimate the sum of two numbers is to round each number and then add the rounded numbers. This probably 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

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