Decide how many figures you want to keep. Let's say it is three places. Look at the fourth number. If it is less than 5, leave the third figure alone. If it is greater than 5, raise the third figure by 1. What to do if it is a 5. There are several ways of dealing with this but the one with which I am the most familiar is to "round to the even number." That is, if the number is 12345, for example, and you want to round to the fourth place, 4 is an even number so that rounds to 12340. If the number is 12335, and we want to round to the fourth place, we would write 12340 (because the 3 is an odd number and 4 is an even number so we round to the even digit).
