How do I round 3.4285 to the nearest thousandths?

First, you put the numbers like this. 

After that, you look at the number after 8.

Numbers below 5: Number 8 stays the same.

Numbers 5 and up: Number 8 goes up one.

So, the answer is 3.429 when 3.4285 is rounded.

A very good answer DragonSlayer,  thumbs up from me.

Thanks, Melody. That was really nice!