Placeholder Image

Subtitles section Play video

  • - [Instructor] In this video we're going to get

  • a little bit of practice divided by a two digit number.

  • So let's say that we have 4,781

  • divided by 32.

  • Pause this video and see if you can figure out

  • what that's going to be.

  • And if there is a remainder,

  • figure out what that remainder is going to be.

  • All right, now let's work on this together.

  • So first let me rewrite 4,781

  • and this is going to be divided by 32.

  • Now whenever we divide by anything

  • that has more than one digit,

  • so it's a little bit of an art.

  • The way we're going to tackle it is

  • a little trial and error using estimation.

  • So we'll start by saying "Hey,

  • "how many times does 32 go into four?"

  • Well, 32 doesn't go into four at all, so then we'll move on.

  • How many times does 32 go into 47?

  • Well it's pretty clear that 32 goes one time into 47.

  • So I'll put the one right over there, above the seven in 47.

  • And if you're saying, "Hey, how did Sal know that?"

  • Well, just remember, two times 32 would be 64.

  • That's more than 47.

  • So 32 goes into 47 one time, and we multiply one times 32.

  • One times two is two, one times three is three.

  • You know that one times 32 is 32.

  • And then we subtract 32 from 47.

  • Let's do that, and we get

  • seven minus two is five

  • and four minus three is one.

  • And the way you make sure that you did that step right

  • is whatever we get over here should be less than 32.

  • If whatever we have here is 32 or greater,

  • that means we could of had a larger number up here.

  • But then our next step is we bring down the eight

  • and we say, "How many times does 32 go into 158?"

  • Now this is a little bit tricky.

  • If you were estimating how many times

  • does 30 go into 150,

  • you might say five.

  • And actually this is for kicks, let's just try that out.

  • Let's see if five works.

  • So let's see, five times two is 10.

  • We'll put zero ones and then

  • we will have one 10 there, carry the one.

  • Fives times three is 15, plus one is 16.

  • So that didn't work out.

  • It almost worked out, but not quite.

  • 160 is larger 158 so five is too much there.

  • So we need to go down to four.

  • So four times two is eight.

  • Four times three is 12.

  • And now we subtract and 158 minus 128,

  • eight mins eight is zero,

  • five tens minus two tens is three tens,

  • and then we have no hundreds.

  • And then this is right, 'cause 30 is less than 32.

  • And then we can bring down,

  • we can bring down that one.

  • Now how many times does 32 go into 301?

  • Well we might be tempted to say,

  • "Well, this is close to 30,

  • "this is close to 300, so maybe it's 10."

  • But 10 times 32 would be 320, so that'd be too much.

  • So I feel good about nine as my estimate.

  • Nine times two is 18, carry the one.

  • Nine times three is 27, plus one is 28.

  • And then we can subtract.

  • We're actually going to have to do a little regrouping here.

  • You might be able to do it in your head.

  • To go from 288 to 301, let's see,

  • you would add 12 to get to 300 and then one more, 13.

  • So you might be able to do it in your head

  • that this is going to be 13, or you could regroup.

  • You could say, "All right, let's see,

  • "one is less than eight, can I regroup from the 10s place?

  • "No, I have nothing there so I have to regroup

  • "from the hundreds place.

  • "So I'm gonna take one of those hundreds,

  • "I'm left with two hundreds left.

  • "And then I'm going to have 10 10s.

  • "And then I could take one of those 10s,

  • "so I have nine 10s left, and give it to the ones place

  • "so now I have 11 ones.

  • "And 11 minus eight is 3, nine 10s minus eight 10s

  • "is one 10, and then hundreds,

  • "200 minus 200 is just a zero."

  • And so there we have it, this is less than 32.

  • We have nothing left to bring down

  • and so we're left with the remainder of 13.

  • So this is going to be equal to 149

  • with a remainder of 13, and we're done.

- [Instructor] In this video we're going to get

Subtitles and vocabulary

Click the word to look it up Click the word to find further inforamtion about it