Dividing a decimal by a whole number example

Let's see if we can compute what 1.86 divided by 2 is. And like always, pause this video and have a go at it. I'll give you a hint: see if you can think about 1.86 as a certain number of hundredths, and then divide that by 2.

All right, now let's work through it together. So, as promised, let's see if we can think of 1.86 as a certain number of hundredths. If we go to the hundredths place, we only see six there, but we could view eight tenths as 80 hundredths. So, you could view the 0.86 as 86 hundredths, and each one is a hundred hundredths. So, we really have 186 hundredths.

This number right over here, I'm going to rewrite as 186 hundredths, and that is what we need to divide by 2. Now, if you're dividing 186 of something by 2, well, it's just going to be 186 divided by 2 of that something. So we could rewrite this as 186 divided by 2, and then that's the number of hundredths this is going to be. So I'll put that in parentheses: so it's going to be that many hundredths—100.

All right, so what is 186 divided by 2? Some of you might be able to do it in your head; some of you might want to use some paper. The way I like to think about it is if I were to take the six ones and divide it by 2, well, that's going to be three ones. And then if I were to take the 18 tens and divide it by 2, that's going to be nine tens. So that gets us to 93.

Now, you could have also thought about it like this: you could have said how many times does 2 go into 186? Let's see, it doesn't go into 1. How many times is it going into 18? 9 times. 9 times 2 is 18; we could subtract, and then you have 0. You bring down that 6, and 2 goes into 6 three times. 3 times 2 is 6; you subtract, and you get no remainder. So either way, you're going to get 93.

And it's 93 what? What's 93 hundredths is what we're talking about—93 hundredths. And now we just want to express 93 hundredths as a decimal. Well, how do we do that? Well, that's going to be zero point. The 90 hundredths is the same thing as nine tenths, and then the three hundredths is, of course, three hundredths—three in the hundredths place. So it's 0.93.

And so we could write it up here: this is going to be equal to 0.93, and we're done.