volume_mute
Estimate the difference: 89,070 - 5,431
publish date: 2025/11/03 09:54:50.506899 UTC
Answer = (1)
Correct Answer
(1) 85000
Explanation
We will use front-end rounding to approximate the 89,070 and 5,431. Then we will find the difference of the approximations. Front-end rounding produces whole numbers containing many 0's. Such numbers are easier to substract.
Both the minuend and the subtrahend are rounded to their largest place value to that all but their first digit is zero. Then we subtract the approximations using vertical form.
| \( \begin{array}{r@{\;}r@{\;}l} 89{,}070 & \rightarrow & \text{ }\text{ }9{,}0000 \\ -\,5{,}431 & \rightarrow & -\,5{,}000 \\ \hline & & 85{,}000 \end{array} \) | Round to the nearest ten thousand. Round to the nearest thousand. |
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.
Reference
Mathematics for college students