When working with estimates, it is smart to be aware of how accurate your estimate is. Sometimes it is ok to only be in the ballpark with your estimate. Sometimes it is important to be more accurate.
Rounding to the nearest 10 will usually be the most accurate estimate you can find by rounding. That’s because your rounded number will be 5 or less from the actual number.
More accurate means closer to the actual number.
Rounding to the nearest hundred will usually be less accurate than rounding to the nearest ten.
Here’s an example of rounding 846 to the nearest ten and hundred:
846 rounded to the nearest 10 is 850. 850 is only 4 ones away from 846, and a fairly accurate estimate.
846 rounded to the nearest 100 is 800. 800 is 46 ones away from 846, and a less accurate estimate than 850.
Practice Problems
Which number would accurately round to 50?
Which number accurately rounds to 800 when rounded to the nearest hundred?
