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Welcome to Level 4 multiplication.

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Let's do some problems.

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Let's see, we had 235 times-- I'm going to use two different

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colors here, so bear with me a second.

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Let's say times 47.

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So you start a Level 4 problem just like you would normally

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do a Level 3 problem.

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We'll take that 7, and we'll multiply it by 235.

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So 7 times 5 is 35.

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7 times 3 is 21, plus the 3 we just carried is 24.

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7 times 2 is 14, plus the 2 we just carried.

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This is 16.

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So we're done with the 7.

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Now we have to deal with this 4.

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Well, since that 4 is in the tens place, we add a 0 here.

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You could almost view it as we're multiplying 235, not by

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4, but we're multiplying it by 40, and that's why

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we put that 0 there.

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But once you put the 0 there, you can treat it just like a 4.

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So you say 4 times 5, well, that's 20.

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Let's ignore what we had from before.

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4 times 3 is 12, plus the 2 we just carried, which is 14.

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4 times 2 is 8, plus the 1 we just carried, so that's 9.

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And now we just add up everything.

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5 plus 0 is 5, 4 plus 0 is 4, 6 plus 4 is 10, carry the 1, and

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1 plus 9, well, that's 11.

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So the answer's 11,045.

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Let's do another problem.

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Let's say I had 873 times-- and I'm making these numbers up on

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the fly, so bear with me-- 873 times-- some high numbers--

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90-- and I'm doing them in different colors, just so you

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hopefully get a better understanding of what

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I'm trying to explain.

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Let's say 97.

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No, I just used a 7.

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Let's make it 98.

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So just like we did before, we go to the ones place first, and

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that's where that 8 is, and we multiply that 8 times 873.

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So 8 times 3 is 24, carry the 2.

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8 times 7 is 56, plus 2 is 58, carry the 5.

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8 times 8 is 64, plus the 5 we just carried.

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That's 69.

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We're done with the 8.

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Now we have to multiply the 9, or we could just do it as

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we're multiplying 873 by 90.

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But multiplying something by 90 is just the same thing as

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multiplying something by 9 and then adding a 0 at the end, so

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that's why I put a 0 here.

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Let's say 9 times 3-- well, first, just to clean up

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things, let's get rid of what we had from before.

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We say 9 times 3 is 27, carry the 2.

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9 times 7 is 63, plus the 2 that we just carried is 65.

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Carry the 6.

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8 times 8 is 72, plus the 6 we just carried.

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That's 78.

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And now we just add again.

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4, 8 plus 7 is 15, 1 plus 9 plus 5 is 15, 1 plus 6 plus

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8 is also 15, and 1 plus 7, that's 8.

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So the answer, hopefully-- I don't have a calculator in

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front of me-- is 85,554, assuming I didn't make

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any careless mistakes.

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Let's do one more problem.

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I think it'll hit the point home.

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The next problem I'm going to do, you can almost do it as a

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Level 5 problem because I'm actually going to multiply two

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three-digit numbers, but it's really the same thing, and

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hopefully, you'll see the pattern.

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So let's say I had 234 times-- and I'm going to use three

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colors now-- let's say 643.

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So first we do the 3, which is in the ones place, and

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we multiply that times 234.

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Well, 3 times 4 is 12, carry the 1.

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3 times 3 is 9, add the 1.

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That's 10, carry the 1.

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3 times 2 is 6, plus 1.

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Well, that's 7.

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And then we've done the-- I think I've made a

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mistake someplace.

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Let me see.

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3 times 4 is 12.

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Oh, no, I think that's correct.

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I was confusing myself.

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OK, now we're ready to do the 4, or the 40, and since it's a

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40 because it's in the tens place, we put a 0 right here.

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We say 4 times 4-- well, let's clean up this stuff at the top.

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I always forget to do that.

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4 times 4, well, that's 16, carry the 1.

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4 times 3, well, that's 12, plus 1, well, that's 13.

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4 times 2 is 8, plus the 1, well, that's 9.

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And now we're done with the 4, or the 40, depending on

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how you want to view it.

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Now we're ready for the 6, or the 600.

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Since it's a 600, we put two zeroes here, and we

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just treat it like a 6.

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Let's clean up what we did before.

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So 6 times 4 is 24, carry the 2.

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6 times 3 is 18, plus 2 is 20, carry the 2.

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6 times 2 is 12, plus 2 is 14.

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And now we add it all up.

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2, 6, 7 plus 3 is 10.

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14, carry the 1.

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1 plus 9 is 10, carry the 1.

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That's 5.

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That's 1.

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I hope you can see.

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I hope it's not falling off the screen, the answer

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I get is a 150,462.

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I think you're ready now to try Level 4

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multiplication problems.

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