Rounding picks the nearer of two neighbors. Find the place, then read the one digit after it.
1Pick the Nearer Neighbor
4.62 rounds to 4.6
To the nearest tenth, 4.62 sits between 4.6 and 4.7. Halfway is 4.65. Left of it is nearer 4.6, so the rule is only a shortcut for this line.
2One Digit Decides
Tenths
Decides
3
.
4
4
8
9
round here
4 < 5
not used
not used
✗ 3.4489 to 3.449 to 3.45 to 3.5
✓ 3.4489 to 3.4
Rounding one place at a time, again and again, can give the wrong answer. Use only the digit just to the right of the place you are rounding to. Here that is 4 hundredths, and 4 is less than 5.
3Down Means Stay
4.62 to 4.5
✗ the 6 dropped
4.62 to 4.6
✓ the 6 held
Rounding down keeps the digit and drops the digits after it. Rounding up adds 1 to the digit and drops the digits after it.
4When 9 Rounds Up
3.49|7 to 3.50
49 hundredths and 1 more is 50 hundredths
3.410
no such digit
3.5
wrong place named
Adding 1 to the 9 makes 10 hundredths, so the tenths digit changes too: 49 hundredths becomes 50 hundredths. Keep the final zero: 3.50 says hundredths, 3.5 says tenths.
