The answer is 880, because, to round to the nearest number (in this case, ten) you look to the number on the right and round it up or down. For example, 875. Look to the right of the 7 (which is in the tens place) and you'll see 5. Remember this, 4 or less you round down. 5 or more you round up. So, since it's a five, round up, and you get 880.
