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Welcome to Level Four multiplication.

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Let's do some problems.

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Let's say we had two hundred thirty-five times--

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I'm going to use two different colors here, so bear with me a second.

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Let's say times forty-seven.

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So you start a Level four problem

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just like you would normally do a Level Three problem.

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We'll take that seven, and we'll multiply it by two hundred thirty-five.

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So seven times five is thirty-five.

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Seven times three is twenty-one, plus the three we just carried is twenty-four.

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Seven times two is fourteen, plus the two we just carried.

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This is sixteen.

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So we're done with the seven.

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Now we have to deal with this four.

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Well, since that four is in the tens place, we add a zero here.

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You could almost view it as we're multiplying two hundred thirty-five, not by four,

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but we're multiplying it by forty,

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and that's why we put that zero there.

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But once you put the zero there, you can treat it just like a four.

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So you say four times five, well, that's twenty.

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Let's ignore what we had from before.

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Four times three is twelve, plus the two we just carried, which is fourteen.

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Four times two is eight, plus the one we just carried, so that's nine.

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And now we just add up everything.

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Five plus zero is five, four plus zero is four, six plus four is ten, carry the one,

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and one plus one plus nine, well, that's eleven.

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So the answer is eleven thousand forty-five.

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Let's do another problem.

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Let's say I had eight hundred seventy-three times--

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and I'm making these numbers up on the fly, so bear with me--

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eight hundred seventy-three times-- some high numbers--

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ninety-- and I'm doing them in different colors,

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just so you hopefully get a better understanding

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of what I'm trying to explain.

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Let's say ninety-seven.

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No, I just used a seven.

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Let's make it ninety-eight.

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

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and that's where that eight is,

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and we multiply that eight times eight hundred seventy-three.

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So eight times three is twenty-four, carry the two.

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Eight times seven is fifty-six, plus two is fifty-eight, carry the five.

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Eight times eight is sixty-four, plus the five we just carried.

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That's sixty-nine.

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We're done with the eight.

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Now we have to multiply the nine,

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or we could just do it as we're multiplying eight hundred seventy-three by ninety.

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But multiplying something by ninety is just the same thing

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as multiplying something by nine and then adding a zero at the end.

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So that's why I put a zero right here.

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Let's say nine times three--

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well, first, just to clean up things, let's get rid of what we had from before.

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We say nine times three is twenty-seven, carry the two.

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Nine times seven is sixty-three, plus the two that we just carried is sixty-five.

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Carry the six.

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Nine times eight is seventy-two, plus the six we just carried.

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That's seventy-eight.

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And now we just add again.

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Four, eight plus seven is fifteen, one plus nine plus five is fifteen,

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one plus six plus eight is also fifteen, and one plus seven, that's eight.

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

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is eighty-five thousand five hundred fifty-four,

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assuming I didn't make 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,

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you can almost do it as a Level Five problem

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because I'm actually going to multiply two three-digit numbers,

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but it's really the same thing, and hopefully, you'll see the pattern.

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So let's say I had two hundred thirty-four times--

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and I'm going to use three colors now--

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let's say six hundred forty-three.

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So first we do the three, which is in the ones place,

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and we multiply that times two hundred thirty-four.

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Well, three times four is twelve, carry the one.

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Three times three is nine, add the one.

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That's ten, carry the one.

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Three times two is six, plus one.

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Well, that's seven.

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And then we've done the--

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I think I've made a mistake someplace.

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Let me see.

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Three times four is twelve.

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Oh, no, I think that's correct.

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I was confusing myself.

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Okay, now we're ready to do the four, or the forty,

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and since it's a forty, because it's in the tens place, we put a zero right here.

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We say four times four--

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well let's clean up the stuff at the top.

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I always forget to do that.

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Four times four, well, that's sixteen, carry the one.

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Four times three, well that's twelve, plus one, well that's thirteen.

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Four times two is eight, plus the one, well that's nine.

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And now we're done with the four, or the forty,

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depending on how you want to view it.

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Now we're ready for the six, or the six hundred.

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Since it's a six hundred, we put two zeros here,

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and we just treat it like a six.

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Let's clean up what we did before.

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So six times four is twenty-four, carry the two.

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Six times three is eighteen, plus two is twenty, carry the two.

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Six times two is twelve, plus two is fourteen.

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And now we add it all up.

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Two. Six. Seven plus three is ten.

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Fourteen, carry the one.

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One plus nine is ten.

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Carry the one.

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That's five, that's one.

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I hope you can see. I hope it's not falling off the screen,

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the answer I get is a one hundred fifty thousand four hundred sixty-two.

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I think you're ready now to try Level Four multiplication problems!