Appropriate accuracy

example

Estimating the Sum

Example: Estimate the sums of and

We round the number to the nearest .

So, is nearest to and is nearest to

Thus the estimated sum

example

Estimating the Difference

Find by estimation method
To find the estimated difference, let us estimate each number to nearest ten thousands.

estimated as

estimated as

Estimated difference
.

example

Estimate the product

Estimate the product

Clearly, each factor is a three digit number. So, we round off each factor to nearest hundreds.
rounds off as
rounds off as
Therefore estimated product