Which decimal rounds to 0.72?

Answer 1

There are infinitely many such numbers. Any number in the interval [0.715, 0.725] will do.

Answer 2

Here are the general rules for rounding:

If the number you are rounding is followed by 5, 6, 7, 8, or 9, round the number up. Therefore: Any decimal from 0.715 to 0.719 can be rounded up to 0.72

If the number you are rounding is followed by 0, 1, 2, 3, or 4, round the number down. Therefore: Any decimal from 0.724 to 0.720 can be rounded down to 0.72.