Round 478.54 to the nearest tenth

478.5 is the answer

A tenth is the number that occurs after the decimal

If the number after the tenth is five or higher, then you round up

If the number after the tenth if four or lower, then the tenth stays the same value as it is

In this case, the Ume after the tenth is exactly four, so the value of the tenth stays the same

So your answer is 478.5