Estimate each difference. See Example 11. 45,333 – 3,410 Reference Example 11 Es...

Estimate each difference. See Example 11.

45,333 – 3,410

Reference Example 11

Estimate the difference: 89,070 – 5,431

Strategy We will use front-end rounding to approximate the 89,070 and 5,431. Then we will find the difference of the approximations.

Why Front-end rounding produces whole numbers containing many 0’s. Such numbers are easier to subtract.

Solution

Both the minuend and the subtrahend are rounded to their largest place value so that all but their first digit is zero. Then we subtract the approximations using vertical form.

The estimate is 85,000. If we calculate 89,070 – 5,431, the difference is exactly

83,639. Note that the estimate is close: It’s only 1,361 more than 83,639.