How you can rounded 85 to the nearest ten.
5 rounds up, so 85 would round up to 90.
4 and lower rounds down 5 and up rounds up.
Just FYI, some folks like to round 5 to the nearest even value, which may be up or down. Beware.
To round 85 to the nearest ten, you need to locate the tens place. The tens place is the digit in the tens position, which is the digit just to the left of the ones place. In this case, the tens place is 8.
To round, look at the ones place, which is the digit to the right of the tens place. If the ones place is 5 or greater, you round the tens place up by adding 1. If the ones place is 4 or less, you keep the tens place as it is.
In this case, the ones place is 5, which means you need to round up. So, to round 85 to the nearest ten, you increase the tens place by 1.
Therefore, rounding 85 to the nearest ten gives you 90.