Multiplication - Process
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LearningTranscript
00:00So today, we're going to learn about multiplication and learn how to multiply two numbers if they
00:07have numbers in the hundreds, tens, and ones place.
00:12With addition and subtraction, you can just line them up and just go top to bottom, straight
00:17down.
00:18In multiplication, there's more steps to the process.
00:21But over here in this white box over here, we're going to put the steps down so after
00:27you get done watching me do this problem and explain it, you can go back and look at these
00:31steps over here when you're doing problems of your own.
00:35So the first step we have is multiplying the number in the ones place.
00:42The number in the ones place right here is the four.
00:47And when I talk about multiplication, I talk about having a broken windshield wiper.
00:55It only goes one way.
00:59So we start and we multiply and we can only go one way and we never come back.
01:06And you'll see what I mean in just a second.
01:09So the first one, we go four times four.
01:12And four times four is sixteen.
01:15So I put my six down here and just like with addition, I put the one in my tens place for
01:21the number sixteen up on top of the number in my tens place, okay?
01:29Sixteen.
01:30Now I multiply this number by the number in my tens place.
01:35Remember like I said, I have a broken windshield wiper.
01:37It moves over.
01:39So four times five is twenty, but I have this one up here.
01:43And I add the number up top.
01:46Four times five is twenty plus one is twenty-one.
01:51So just like before, I put my one down here, I'll raise it up a little bit, and I put my
02:02two on top of the number in my hundreds place.
02:06Bring it right on over, okay?
02:10And finally I'm going to multiply four times three, the number in my hundreds place.
02:16And just like before, I'm going to add the number up top.
02:19Four times three is twelve, plus two is fourteen, okay?
02:27So I have my four down here.
02:31And since there's nowhere, I can't put my one up top anywhere, I have no thousands.
02:37I'll bring my one down here too, okay?
02:41So that brings us to the next step.
02:43The next step is put a zero, let me bring it down, put a zero below in the ones place
02:52to hold its place.
02:53That means right here.
02:55Right here I'm going to put a zero.
02:57The reason why is because we are now multiplying by tens, okay?
03:05I'm not just multiplying by six now, I'm going to multiply basically by six groups of ten.
03:09So I don't need anything in my ones place.
03:11I'm putting the zero to hold its place to make sure I don't put anything in that ones
03:16place, okay?
03:17And I'm going to actually cross out these numbers up here.
03:21Just put a line right through them.
03:22I'm not going to erase them because if I make a mistake on my addition, have to go back
03:27and check, I want to know that wait, I did have a two and I did have a one up here.
03:32I put a simple line through them to know I'm not going to use them anymore, okay?
03:36And after I put that zero to hold its place, I'm going to multiply by the number in the
03:43tens place.
03:44In this case, the number in the tens place is six.
03:49Like I said earlier, I'm multiplying by six tens.
03:51And just like before, I have my broken windshield wiper.
03:56It only goes this way.
03:58Only goes to the left, okay?
04:01So let me get rid of that to give us some space.
04:03Now six times four is twenty-four.
04:07So since I'm multiplying by six tens, I'm going to put it right below in the tens place.
04:14So I have that zero there, the purple zero, okay, to hold its place.
04:19And I need to put that two and twenty-four up over here, okay?
04:26Now I'm going to multiply it like my windshield wiper says, go right next door.
04:31Six times five is thirty, but now I crossed out that one because I don't need it anymore,
04:36but I have a two up here.
04:38Six times five is thirty plus two is thirty-two.
04:45So I put my two down here in thirty-two.
04:49And I put my three up top next to the hundreds, okay?
04:55And again, that's why I crossed out that two because I don't need it anymore.
04:58I'm going to multiply six times three now.
05:02Six times three is eighteen, okay?
05:07Eighteen plus three is twenty-one, okay?
05:14Now just like before, I put my one down here.
05:20And since I have nowhere else to put my two, I don't have any numbers in the thousands
05:26place.
05:27So I'm not doing any more multiplying.
05:29I put it right next to it, okay?
05:33Raise it up just to make it nicer, okay?
05:36Now that leads us to the last step.
05:40Add them up, okay?
05:42So I'm going to put a plus sign right here, and I'm going to put an equal sign right here.
05:50I'm going to add them up to find my answer.
05:53I multiplied by all of my ones, I multiplied by all of my tens, and now I'm going to add
06:00them up.
06:01Six plus zero is six.
06:06One plus four is five.
06:13Four plus two is six.
06:19One plus one is two, and two plus zero, because there's nothing on top of it, is two, okay?
06:36So I multiplied by the number in my ones place, and I got one thousand four hundred sixteen.
06:42I put my zero down below in the ones place to hold its place because now I'm multiplying
06:46by six tens.
06:48Now when I multiply this number by six tens, I had twenty-one thousand two hundred forty.
06:55I wasn't done.
06:57After that, I put my plus sign, my equal sign, and I added them up.
07:02So when you're done, three hundred and fifty-four times sixty-four equals twenty-two thousand
07:09six hundred and fifty-six, okay?
07:13I'm leaving these steps right here so you can always refer back to these.
07:19If you know these four steps, multiplying a three-digit number or a two-digit number
07:24by a two-digit number with tens in the ones is quite easy because you're always going
07:29to do this right here.