When rounding to the "nearest whole number" you will need to either round up or down.
If its within 1 2 3 or 4 you round down, so if our number was 73, the nearest whole number would be 70.
Our question here consist of 76.78.
Well just by looking at the first part of the number, 76, we already know that we are rounding up. so in doing this, I was able to get 80 because when 5 6 7 8 or 9 you round up.