How to Estimate a difference by rounding.

• Round each decimal term that will be subtracted.
• Subtract the rounded terms

Example: Estimate the difference of 0.988 - 0.53

• Round 0.988 - 0.53 to 1 - 0.5
• Subtract the rounded numbers to obtain the estimated difference of 0.5
• The actual difference of 0.988 - 0.53 is 0.458

Some uses of rounding are:

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