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 is less than 5
no vote
no vote
✗ 3.4489 to 3.449 to 3.45 to 3.5
✓ 3.4489 to 3.4
Rounding again and again walks a number up one place at a time. Only the digit next to the place you want votes. 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 does not lower the digit. It holds the digit and clears what follows. Up bumps it by one. Those are the only two moves.
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
A 9 has nowhere to go, so the carry moves two places at once. Keep the final zero: 3.50 says hundredths, 3.5 says tenths.
