Look at the place you want to round to. I'll call it the place. I'm using the tenths place as an example.

4.**1**431 7.**7**923

Look one place directly to the right of it. I'll call that the digit.

4.**14**31 7.**79**23

If the digit is 0, 1, 2, 3, or 4, the place stays the same. If the digit is 5, 6, 7, 8, or 9, the place increases by 1. All numbers behind the place become zeroes.

4.1431 ----> 4.100 or 4.1 7.7923 ----> 7.800 or 7.8

You may have to do this.

1.9503 ----> 2.0000 or 2

Most problems specify the place you need to round to.

Note that if you aren't rounding to a decimal, the zeroes cannot be omitted (ignored).