When rounding 270 to the nearest ten, you look at the digit in the tens place, which is 7. Since 7 is greater than or equal to 5, you round up. Therefore, 270 rounded to the nearest ten is 280.
Well, honey, 270 rounded to the nearest ten is 270. It's already sitting pretty on that ten, so there's no need to push it one way or the other. Just let it be.