Here's the whole rule: find the place you're rounding to, look at the very next digit, and decide. If that next digit is 5 or more, round up; if it's less than 5, round down (leave the kept digit as is). Then chop off everything after.
The Three Moves
One — find the place you're keeping. To 1 decimal place? Keep down to the tenths. To the nearest whole? Keep down to the ones.
Two — look at the next digit along. This is the decider — the first digit you're about to throw away.
Three — apply the rule. Decider is 5, 6, 7, 8 or 9 → bump the kept digit up by one. Decider is 0, 1, 2, 3 or 4 → leave it. Either way, drop the rest.
A Worked One
Round 7.382 to 1 decimal place. The kept place is the tenths (the 3). The decider is the next digit, 8. Since 8 is 5 or more, round up: the 3 becomes a 4. Drop the rest. Answer: 7.4.
Same Rule, Any Accuracy
It doesn't matter if you're rounding to a whole, a tenth, or a hundredth — the moves are identical, you just keep down to a different place. Round 0.0473 to 2 decimal places: keep the hundredths (the 4), decider is 7, round up → 0.05.