When you are doing rounding you look at the number you are rounding. It is very important that you know  your place value. If the number one place value behind bigger than five round it up. For example 79 is rounded to 80 .  Rounding is a life skill we need to know how to do for a few jobs. Like in a school you are buying pencils you will round the children to the nearest hundred so you can estemate how many. And for work when you need to copy some sheets you round to see how many you need approximately. Rounding and estimating sometimes go togeth like in the examples I gave you.