## Video transcript

It never hurts to get a lot ofpractice, so in this video I'm just going to do a bunch moreof essentially, what we call long division problems. And so if you have4 goes into 2,292. And I don't know exactly whythey call it long division, and we saw this in thelast video a little bit. I didn't call it long divisionthen, but I think the reason why is it takes you a longtime or it takes a long piece of your paper. As you go along, you kind ofhave this thing, this long tail that develops on the problem. So all of those are, at least,reasons in my head why it's called long division. But we saw in the last videothere's a way to tackle any division problem while justknowing your multiplication tables up to maybe 10times 10 or 12 times 12. But just as a bit of review,this is the same thing as 2,292 divided by 4. And it's actually the samething, and you probably haven't seen this notation before,as 2,292 divided by 4. This, this, and this areall equivalent statements on some level. And you could say, hey Sal,that looks like a fraction in case you have seenfractions already. And that is exactly what it is. It is a fraction. But anyway, I'll just focus onthis format and in future videos we'll think about otherways to represent division. So let's do this problem. So 4 goes into 2how many times? It goes into 2 no times,so let's move on to-- let me just switch colors. So let's move on to the 22. 4 goes into 22 how many times? Let's see. 4 times 5 is equal to 20. 4 times 6 is equal to 24. So 6 is too much. So 4 goes into 22 five times. 5 times 4 is 20. There's going to be alittle bit of a leftover. And then we subtract22 minus 20. Well that's just 2. And then you bring down this 9. And you saw in the last videoexactly what this means. When you wrote this 5 uphere-- notice we wrote in the 100's place. So this is really a 500. But in this video I'm justgoing to focus more on the process, and you can think moreabout what it actually means in terms of where I'mwriting the numbers. But I think the processis going to be crystal clear hopefully, bythe end of this video. So we brought down the 9. 4 goes into 29 how many times? It goes into atleast six times. What's 4 times 7? 4 times 7 is 28. So it goes into it atleast seven times. What's 4 times 8? 4 times 8 is 32, so it can't gointo it eight times so it's going to go into it seven. 4 goes into 29nine seven times. 7 times 4 is 28. 29 minus 28 to get ourremainder for this step in the problem is 1. And now we're going tobring down this 2. We're going to bring itdown and you get a 12. 4 goes into 12? That's easy. 4 times 3 is 12. 4 goes into 12 three times. 3 times 4 is 12. 12 minus 12 is 0. We have no remainder. So 4 goes into 2,292exactly 573 times. So this 2,292 divided by 4we can say is equal to 573. Or we could say that this thingright here is equal to 573. Let's do a couple of more. Let's do a few more problems. So I'll do that red color. Let's say we had 7going into 6,475. Maybe it's called long divisionbecause you write it nice and long up here and youhave this line. I don't know. There's multiple reasons why itcould be called long division. So you say 7 goesinto 6 zero times. So we need to keepmoving forward. So then we go to 64. 7 goes into 64 how many times? Let's see. 7 times 7 is? Well, that's way too small. Let me think aboutit a little bit. Well 7 times 9 is 63. That's pretty close. And then 6 times 10 isgoing to be too big. 7 times 10 is 70. So that's too big. So 7 goes into 64 nine times. 9 times 7 is 63. 64 minus 63 to get ourremainder of this stage 1. Bring down the 7. 7 goes into 17 how many times? Well, 7 times 2 is 14. And then 7 times 3 is 21. So 3 is too big. So 7 goes into 17 two times. 2 times 7 is 14. 17 minus 14 is 3. And now we bring down the 5. And 7 goes into 35? That's in our 7 multiplicationtables, five times. 5 times 7 is 35. And there you go. So the remainder is zero. So all the examples I didso far had no remainders. Let's do one that maybemight have a remainder. And to ensure it has aremainder I'll just make up the problem. It's much easier to makeproblems that have remainders than the ones thatdon't have remainders. So let's say I want to divide 3into-- I'm going to divide it into, let's say 1,735,092. This will be a nice,beastly problem. So if we can do this wecan handle everything. So it's 1,735,092. That's what we'redividing 3 into. And actually, I'm not sure ifthis will have a remainder. In the future video I'll showyou how to figure out whether something is divisible by 3. Actually, we cando it right now. We can just add upall these digits. 1 plus 7 is 8. 8 plus 3 is 11. 11 5 five is 16. 16 plus 9 is 25. 25 plus 2 is 27. So actually, this numberis divisible by 3. So if you add up all ofthe digits, you get 27. And then you can add up thosedigits-- 2 plus 7 is 9. So that is divisible by 9. That's a trick thatonly works for 3. So this number actuallyis divisible by 3. So let me change it alittle bit, so it's not divisible by 3. Let me make this into a 1. Now this number willnot be divisible by 3. I definitely want anumber where I'll end up with a remainder. Just so you see whatit looks like. So let's do this one. 3 goes into 1 zero times. So we can just move forward. You could write a 0 here andmultiply that out, but that just makes it a littlebit messy in my head. So we just moveone to the right. 3 goes into 17 how many times? Well, 3 times 5 is equal to 15. And 3 times 6 is equal to18 and that's too big. So 3 goes into 17 righthere five times. 5 times 3 is 15. And we subtract. 17 minus 15 is 2. And now we bring down this 3. 3 goes into 23 how many times? Well, 3 times 7 is equal to 21. And 3 times 8 is too big. That's equal to 24. So 3 goes into 23 seven times. 7 times 3 is 21. Then we subtract. 23 minus 21 is 2. Now we bring downthe next number. We bring down the 5. I think you can appreciate whyit's called long division now. We bring down this 5. 3 goes into 25 how many times? Well, 3 times 8 gets you prettyclose and 3 times 9 is too big. So it goes into it eight times. 8 times 3 is 24. I'm going to run out of space. You subtract, you get 1. 25 minus 24 is 1. Now we can bring down this 0. And you get 3 goes into10 how many times? That's easy. It goes into it three times. 3 times 3 is 9. That's about as closeto 10 as we can get. 3 times 3 is 9. 10 minus 9, I'm going tohave to scroll up and down here a little bit. 10 minus 9 is 1, and then wecan bring down the next number. I'm running out of colors. I can bring down that 9. 3 goes into 19 how many times? Well, 6 is about asclose as we can get. That gets us to 18. 3 goes into 19 six times. 6 times 3-- let me scroll down. 6 times 3 is 18. 19 minus 18-- we subtractit up here too. 19 minus 18 is 1 andthen we're almost done. I can revert back to the pink. We bring down this1 right there. 3 goes into 11 how many times? Well, that's three timesbecause 3 times 4 is too big. 3 times 4 is 12, sothat's too big. So it goes into it three times. So 3 goes into 11 three times. 3 times 3 is 9. And then we subtractand we get a 2. And there's nothingleft to bring down. When we look up here there'snothing left to bring down, so we're done. So we're left with theremainder of 2 after doing this entire problem. So the answer, 3 goes into1,735,091-- it goes into it 578,363 remainder 2. And that remainder 2 was whatwe got all the way down there. So hopefully you now appreciateand you can tackle pretty much any division problem. And you also, through thisexercise, can appreciate why it's called long division.