So I answered one of your rounding questions before. I am going to give you some math rules so that you can do it on your own.
If you are rounding to the hundreds place and the number in the tens place is 4 or less, the number in the hundreds place stays the same and the other places are 0.
If you are rounding to the hundreds place and the number in the tens place is 5 or more, the number in the hundreds place increases by 1 and the other places are 0.
The answer to your question is 400.
Happy to help!!
