Rounding a two-place decimal to the nearest tenth: the hundredths digit decides, and the answer keeps one decimal place. 3.28 rounds to 3.3, and 3.25 rounds to 3.3 as well - half rounds up here exactly as it does with whole numbers.
The answer is written to the place it was rounded to, so 3.28 rounds to 3.3, not 3.30. A trailing zero would claim a precision the rounding threw away.
Look at the hundredths digit. 5 or more rounds the tenths digit up; 4 or less leaves it. Then drop everything after the tenths place.
3.3. The deciding digit is 5, and half rounds up - the same rule as whole numbers. These half-way cases are put on each sheet deliberately.
Because it was rounded to the nearest tenth, so the tenths place is as far as the answer goes. Writing 3.30 would suggest the hundredths digit is known to be zero, and rounding just discarded it.
Turn on Include Answer Pages and a matching key prints behind each worksheet page, with the questions in the same order.