Description: In this example where we subtract decimals we do so up to the thousandths place. It's a little tricky, but not if we do it together. Created by Sal Khan. Let's try to calculate 39.1 minus 0.794, and so pause the video and try this on your own. So what we could do is take this one tenth and try to regroup it into the hundredths place and the thousandths place. Well we could do it, but then we're going to have zero tenths, and we're still going to have a problem here.*Teacher Advisor is 100% free.