Estimating products means using place-value reasoning to round whole-number factors, or choose compatible numbers, and then multiply to obtain a reasonable approximation of a product, typically for one- and two-digit factors and products involving numbers up to the thousands. The estimate preserves the product’s approximate size and supports judging whether an exact calculation is reasonable; decimal, fraction, and formal error-bound estimates are beyond this scope.
To estimate a product, round the factors to friendly numbers that are easy to multiply. The answer will be close to the exact product, but it will be quicker to find.
Example: Estimate .
Round each factor to the nearest ten:
Multiply the rounded numbers:
So, is about 800. This makes sense because is close to and is close to .
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