Find the two neighbouring tens
To round a positive whole number to the nearest ten, choose the multiple of ten that is closest. Here we use the common school convention: an exact halfway value goes to the higher ten.
Think of 28 standing between 20 and 30. It is eight steps from 20 and only two from 30, so it rounds to 30. The original number is still 28; 30 is a simpler approximation.
Let the ones digit do the checking
OpenStax explains rounding through place value and a number line. For the nearest ten, look at the ones digit. If it is 0, 1, 2, 3 or 4, keep the lower ten. If it is 5, 6, 7, 8 or 9, choose the higher ten.
83 rounds to 80: its ones digit is 3. 87 rounds to 90: its ones digit is 7. A number already ending in zero, such as 80, stays where it is.
What happens exactly halfway?
65 is five steps from 60 and five from 70. Distance alone gives a tie. Under the convention used in this lesson, 65 rounds to 70.
That convention needs stating because other rounding methods exist. We are working with positive whole numbers and the nearest ten here, rather than trying to cover every rule used in computing or statistics.
Sometimes the next ten changes a hundred
95 sits halfway between 90 and 100, so it rounds to 100. Likewise, 198 is closer to 200 than to 190. You can cross a hundred while rounding to the nearest ten.
If this feels slippery, return to tens and ones. To use a rounded number in an exact calculation, see rounding and adjusting: the adjustment restores what the shortcut changed.