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In the last video we went over the multiplication tables for 1

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through 9 and I ran out of time, and actually, it was a

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good thing because 1 through 9 are kind of the core

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multiplication tables.

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And you'll see that if you know all your multiplication tables

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from 1 to 9, so you know any number between 1 and 9 times

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any other number between 1 and 9, you can actually do

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any multiplication problem out there.

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But what I want to do now is I want to complete the

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multiplication tables for 10, 11, and 12.

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So what is 10 times-- let's just start with 0.

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10 times 0.

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Anything times 0 is 0.

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Ten 0's are 0.

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0 plus 0 plus 0 ten times is still 0.

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What's 10 times 1?

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Well that's just 10 one time.

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Or 1 plus itself ten times.

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That's 10.

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I think this is second nature to you at this point.

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What's 10 times 2?

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I meant to switch colors, but I didn't.

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10 times 2?

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That's 10 plus 10, which is 20.

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Fair enough.

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And notice, we went up by 10 the first time.

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We went up by 10 again to get to 20.

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What's 10 times 3?

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Well, that's 10 plus 10 plus 10, or we could view it as 10

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times 2 plus another 10, which is equal to 30.

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What's 10 times 4?

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I think you start to see a pattern.

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10 times 4 is equal to 40.

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Notice, 10 times 4 is equal to 40.

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If I were to tell you what is 10 times-- let me

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do another color-- 5?

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Well that's equal to 50.

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10 times anything is that anything with a 0 behind it.

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So the 10 times tables you almost don't

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have to remember it.

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So let's just keep going.

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What's 10 times 6?

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It's equal to 60.

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6 0.

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What's 10 times 7?

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70.

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10 times 8?

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This is almost ridiculous.

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10 times 8 is 80.

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10 times 9?

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90.

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10 times 10?

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Now this is interesting.

56
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So it'll be a 10-- let's see me write this.

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Let me do it in this orange color.

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10 times 10.

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So it'll be ten 10's or a 10 with a 0 behind it.

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There you go.

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Notice everything-- whatever times 10 I just add a 0 and

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then I get the next number.

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So it's 100.

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And I think you understand why that is.

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I added 10 to itself ten times.

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That each 10-- you go from 10, 20, 30.

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30 is just three 10's or 10 times 3.

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90 is just nine 10's or 9 times 10.

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Let's keep going.

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So 10 times 11 is equal to 11 with a 0 behind it.

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110.

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Finally, 10 times 12 is equal to 120.

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Now, just for fun, these are kind of your 10 times tables.

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But now that t know the pattern you can do anything.

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If I asked you what 5,732 times 10 is, what's it going to be?

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It's going to be this number with just one more 0.

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So it's going to be-- I won't read it out yet.

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5 7 3 2 with a 0 behind it.

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And just so you know, this little comma that I wrote in

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the number there, that's just to make it easier for

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me to read that number.

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And you put the comma-- you start over here and every third

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number you put the comma.

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So here I'm going to put the comma right here.

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I'm going to put the comma right there.

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So now I can read this.

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The comma doesn't really add or take anything away from

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the number, it just helps me read it.

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Now 5,732 times 10 is 57,320.

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i just had to add a 0 there, but that was a pretty

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straightforward multiplication.

93
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And notice, we had 5,000 times 10 and we got to 50 something

94
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thousand when we multiplied them.

95
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So that's similar to 5 times 10 is equal to 50.

96
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But instead of 5 I had a 5,000, and so I got a 50,000 and

97
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something and all this other stuff.

98
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We're going to learn more about how to do problems

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like this in the future.

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But I thought I would introduce you to the idea that just from

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this little pattern of adding a 0 you already know your

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10's times tables.

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Now let's do our 11's.

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105
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Well, they start off easy, and then they get a little more

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difficult as we get into high numbers.

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11 times 0.

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This is easy, this is 0.

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11 times 1.

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This is also easy.

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It's 11.

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11 times 2.

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We're going to start seeing a pattern here.

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It's 11 plus 11 or we could've added 2 to itself eleven times,

115
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but that is equal to 22.

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If we do 11 times 3 it is equal to 33.

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11 times 4 is equal to 44.

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I think this is becoming obvious to you.

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What's 11 times 5?

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11 times 5 is 55.

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Notice I put the 5 twice.

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What's 11 times 6?

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It's 66.

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11 times 7 is 84-- no.

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I'm kidding.

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I didn't want to mess with you like that.

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But no.

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Of course, it's 77.

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You just repeat the number twice.

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Let me switch colors.

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11 times 8 is equal to 88.

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11 times 9 is equal to 99.

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Now what's 11 times 12?

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136
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Oh sorry, I skipped 10.

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11 times 10.

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You might want to say it's 1,010.

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No.

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That's wrong.

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It's not 1,010.

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So that little pattern that we had where you just repeat the

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number, that only worked for one-digit numbers.

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So it only worked for 1 through 9.

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11 times 10?

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Well, we could think about it a couple of ways.

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We can add 11 to 99.

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So we can say it's 99 plus 11.

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And what's that?

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That's equal to 110.

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And I'm going to show you how to do-- well, hopefully you've

152
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already watched the video on how to add two-digit numbers

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like this, but that's 110.

154
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Or you could just use the property from the 10's times

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tables that we learned where if you just take 11 times 10 you

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add a 0 to the 11, you get 110.

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That's the 11 right there.

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Finally, let's do 11 times 12.

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No easy way to remember this, you just kind of

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should remember it.

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Or you could say look, it's going to be 11 more

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than 11 times-- sorry.

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I keep skipping things.

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We should do 11 times 11 first.

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Let me make sure this is clear.

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We're doing 11 times 11 before we go to 11 times 12.

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So 11 times 11 is going to be 11 more than 11 times 10.

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So we add 11 to this.

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11 plus 110 is 121.

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And actually, as you'll see, there actually is an order as

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we get to higher multiples of 11, but I'll leave that

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to a future video.

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And then finally, we're at 11 times 12.

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And we could add 11 to itself twelve times.

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We could add 12 to itself eleven times.

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Or we could just say, hey, is going to be 11 more

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than 11 times 11.

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So that is what?

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You add 11 to this.

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What do you get?

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You get 132.

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I just added 121 plus 11 and then got 132.

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Now the other way you could have said it is, well,

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00:07:52,605 --> 00:07:54,900
what's 10 times 12?

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00:07:54,899 --> 00:07:56,169
We already knew that.

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That was 120.

189
00:07:58,579 --> 00:08:02,979
So 11 times 12 because we're multiplying 12 by one more

190
00:08:02,980 --> 00:08:04,939
should be 12 more than that.

191
00:08:04,939 --> 00:08:06,709
So that should be 132.

192
00:08:06,709 --> 00:08:10,099
So two ways to get the exact same answer.

193
00:08:10,100 --> 00:08:12,785
All right, now let's do our 12 times tables.

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195
00:08:15,329 --> 00:08:18,649
And once you know this you are ready to tackle any type

196
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of multiplication problem.

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00:08:19,745 --> 00:08:21,995
But we'll do that in future videos.

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So 12 times 0.

199
00:08:24,000 --> 00:08:24,800
Super easy.

200
00:08:24,800 --> 00:08:25,350
0.

201
00:08:25,350 --> 00:08:26,430
12 times 1.

202
00:08:26,430 --> 00:08:27,334
Also super easy.

203
00:08:27,334 --> 00:08:28,489
Is 12.

204
00:08:28,490 --> 00:08:29,930
Now it gets interesting.

205
00:08:29,930 --> 00:08:33,509
We're going to increase by 12 every time.

206
00:08:33,509 --> 00:08:37,000
12 times 2 is equal to 24.

207
00:08:37,000 --> 00:08:39,899
12 plus 12 is 24.

208
00:08:39,899 --> 00:08:43,240
12 times-- not 22.

209
00:08:43,240 --> 00:08:44,169
Let me rewrite that.

210
00:08:44,169 --> 00:08:50,259
12 times 3 is going to be 12 plus 12 plus 12.

211
00:08:50,259 --> 00:08:53,990
Or we could write that as 12 times 2.

212
00:08:53,990 --> 00:08:56,070
I see my brain is doing the wrong things.

213
00:08:56,070 --> 00:09:00,680
We could rewrite that as 12 times 2 plus 12.

214
00:09:00,679 --> 00:09:03,779
Or we could rewrite that as 24 plus 12.

215
00:09:03,779 --> 00:09:07,039
Either way, all of these get us to 36.

216
00:09:07,039 --> 00:09:10,409
And notice, that's just that plus 12.

217
00:09:10,409 --> 00:09:12,250
12 times 4.

218
00:09:12,250 --> 00:09:17,190
12 times 4 is equal to 48.

219
00:09:17,190 --> 00:09:18,275
There's a lot of ways you could think about it.

220
00:09:18,274 --> 00:09:19,980
You could say 11 times 4 is 44.

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00:09:19,980 --> 00:09:25,670


222
00:09:25,669 --> 00:09:30,029
And you go up by one more 4, so you get to 12 times 4.

223
00:09:30,029 --> 00:09:33,629
Or you could say 12 times 3 is 36 and you can add one

224
00:09:33,629 --> 00:09:36,950
12 to it to get to 48.

225
00:09:36,950 --> 00:09:39,235
Either way works and that's because you can multiply

226
00:09:39,235 --> 00:09:40,310
in either direction.

227
00:09:40,309 --> 00:09:42,309
Let's keep going.

228
00:09:42,309 --> 00:09:47,849
12 times 5 is equal to 60.

229
00:09:47,850 --> 00:09:55,340
10 times 5 is 50, 11 times 5 is 55, so 12 times 5 is 60.

230
00:09:55,340 --> 00:09:58,665
12 times 6 is equal to what?

231
00:09:58,664 --> 00:10:00,579
It's going to be 12 more than this.

232
00:10:00,580 --> 00:10:02,639
It's going to equal 72.

233
00:10:02,639 --> 00:10:04,519
12 times 7.

234
00:10:04,519 --> 00:10:06,720
12 more than this again.

235
00:10:06,720 --> 00:10:09,470
12 more than 72 is 84.

236
00:10:09,470 --> 00:10:15,889
And I'm serious, I'm probably a lot older than you are and I

237
00:10:15,889 --> 00:10:19,199
still, in my head to confirm, I go to some 12 times tables that

238
00:10:19,200 --> 00:10:20,700
I remember as definitely right.

239
00:10:20,700 --> 00:10:23,290
Like oh, 12 times 5-- and sometimes in my head I say,

240
00:10:23,289 --> 00:10:24,099
oh, let me add another 12.

241
00:10:24,100 --> 00:10:26,300
Oh yeah, definitely, my memory was correct.

242
00:10:26,299 --> 00:10:28,490
12 times 6 is 72.

243
00:10:28,490 --> 00:10:29,029
All right.

244
00:10:29,029 --> 00:10:31,329
Then you go to 12 times 8.

245
00:10:31,330 --> 00:10:34,100
Add 12 to the 12 times 7.

246
00:10:34,100 --> 00:10:35,409
96.

247
00:10:35,409 --> 00:10:38,985
12 times 9 .

248
00:10:38,985 --> 00:10:44,350
Well you add 12 to this, so it's 108.

249
00:10:44,350 --> 00:10:46,700
And then 12 times 10.

250
00:10:46,700 --> 00:10:48,680
This is an easy one.

251
00:10:48,679 --> 00:10:51,389
We just add a 0 to the 12 to get 120.

252
00:10:51,389 --> 00:10:54,210
Or we could've added 12 to 108.

253
00:10:54,210 --> 00:10:55,570
Either way.

254
00:10:55,570 --> 00:10:58,300
12 times 11.

255
00:10:58,299 --> 00:10:59,419
We just did this.

256
00:10:59,419 --> 00:11:02,000
You add 12 to this you get to 132.

257
00:11:02,000 --> 00:11:09,000
And then 12 times 12 is equal to 144.

258
00:11:09,000 --> 00:11:10,169
And this actually shows up.

259
00:11:10,169 --> 00:11:13,529
If I had a dozen of a dozen eggs-- a dozen is 12.

260
00:11:13,529 --> 00:11:17,019
Or if I had, I think a gross is actually 12 dozens.

261
00:11:17,019 --> 00:11:18,419
So that's 144 eggs.

262
00:11:18,419 --> 00:11:20,709
You'll actually end up seeing this number a lot.

263
00:11:20,710 --> 00:11:22,560
More than you would expect in life.

264
00:11:22,559 --> 00:11:25,719
But anyway, we've now completed all of our

265
00:11:25,720 --> 00:11:27,420
multiplication tables.

266
00:11:27,419 --> 00:11:29,789
And I really encourage you to take the time now to

267
00:11:29,789 --> 00:11:30,929
go and memorize them.

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Make some flash cards.

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Use the little software thing that I wrote on my website.

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You could try that out.

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As of September 2009 it's working.

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I haven't touched it in a while, but I'm actually

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probably going to rebuild it soon.

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So if you're watching this video in the year 2200.

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Well, I would probably not exist anymore.

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But hopefully you'll get a better version of

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the software app.

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But you should practice it.

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You should get your parents to quiz you.

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You should get notes cards.

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You should just be mumbling to yourself as you walk to

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school-- what is 12 times 9?

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What is 11 times 11?

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And you should quiz each other because it'll pay huge rewards

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to you later on in life.

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See you in the next video.