1 00:00:00,540 --> 00:00:04,565 In the last video we went over the multiplication tables for one through nine 2 00:00:04,565 --> 00:00:06,960 and I ran out of time, and actually, it was a good thing 3 00:00:06,960 --> 00:00:11,266 because one through nine are kind of the core multiplication tables. 4 00:00:11,266 --> 00:00:14,702 And you'll see that if you know all your multiplication tables from one to nine, 5 00:00:14,702 --> 00:00:16,720 so you know any number between one and nine 6 00:00:16,720 --> 00:00:18,816 times any other number between one and nine, 7 00:00:18,816 --> 00:00:21,670 you can actually do any multiplication problem out there. 8 00:00:21,670 --> 00:00:22,642 But what I want to do now 9 00:00:22,642 --> 00:00:29,810 is I want to complete the multiplication tables for ten, eleven, and twelve. 10 00:00:29,820 --> 00:00:33,680 So what is ten times-- let's just start with zero. 11 00:00:33,680 --> 00:00:35,980 Ten times zero. 12 00:00:35,990 --> 00:00:39,030 Anything times zero is zero. 13 00:00:39,030 --> 00:00:40,375 Ten zeros are zero. 14 00:00:40,375 --> 00:00:43,933 Zero plus zero plus zero ten times is still zero. 15 00:00:43,933 --> 00:00:46,107 What's ten times one? 16 00:00:46,122 --> 00:00:48,034 Ten times one. 17 00:00:48,034 --> 00:00:49,982 Well that's just ten one time. 18 00:00:49,990 --> 00:00:52,740 Or one plus itself ten times. 19 00:00:52,750 --> 00:00:53,890 That's ten. 20 00:00:53,890 --> 00:00:56,490 I think this is second nature to you at this point. 21 00:00:56,500 --> 00:00:58,447 What's ten times two? 22 00:00:58,447 --> 00:00:59,961 Ten times two. 23 00:00:59,961 --> 00:01:02,660 I meant to switch colors, but I didn't. 24 00:01:02,670 --> 00:01:04,060 Ten times two? 25 00:01:04,060 --> 00:01:08,950 That's ten plus ten, which is twenty. 26 00:01:08,950 --> 00:01:09,550 Fair enough. 27 00:01:09,560 --> 00:01:12,650 And notice, we went up by ten the first time. 28 00:01:12,650 --> 00:01:15,210 We went up by ten again to get to twenty. 29 00:01:15,210 --> 00:01:17,690 What's ten times three? 30 00:01:17,700 --> 00:01:20,546 Well, that's ten plus ten plus ten, 31 00:01:20,546 --> 00:01:24,539 or we could view it as ten times two plus another ten, 32 00:01:24,539 --> 00:01:26,485 which is equal to thirty. 33 00:01:26,485 --> 00:01:27,385 What's ten times four? 34 00:01:27,385 --> 00:01:28,670 I think you start to see a pattern. 35 00:01:28,680 --> 00:01:32,450 Ten times four is equal to forty. 36 00:01:32,450 --> 00:01:37,400 Notice, ten times four is equal to forty. 37 00:01:37,400 --> 00:01:42,030 If I were to ask you what is ten times-- 38 00:01:42,040 --> 00:01:44,860 let me do another color-- five? 39 00:01:44,870 --> 00:01:50,260 Well that's equal to fifty. 40 00:01:50,260 --> 00:01:56,410 Ten times anything is that anything with a zero behind it. 41 00:01:56,410 --> 00:01:57,702 So the ten times tables, 42 00:01:57,702 --> 00:01:59,315 you almost don't have to remember it. 43 00:01:59,315 --> 00:02:01,378 So let's just keep going. 44 00:02:01,378 --> 00:02:04,109 What's ten times six? 45 00:02:04,109 --> 00:02:06,840 It's equal to sixty. 46 00:02:06,840 --> 00:02:08,340 Six zero. 47 00:02:08,340 --> 00:02:11,090 What's ten times seven? 48 00:02:11,090 --> 00:02:12,315 Seventy. 49 00:02:12,315 --> 00:02:13,340 Ten times eight? 50 00:02:13,340 --> 00:02:14,920 This is almost ridiculous. 51 00:02:14,930 --> 00:02:16,810 Ten times eight is eighty. 52 00:02:16,810 --> 00:02:19,020 Ten times nine? 53 00:02:19,030 --> 00:02:20,315 Ninety. 54 00:02:20,315 --> 00:02:21,590 Ten times ten? 55 00:02:21,590 --> 00:02:23,708 Now this is interesting. 56 00:02:23,708 --> 00:02:26,882 Ten times ten, so it'll be a ten-- 57 00:02:26,882 --> 00:02:29,523 let's see me write this. 58 00:02:29,523 --> 00:02:32,180 Let me do it in this orange color. 59 00:02:32,180 --> 00:02:33,302 Ten times ten. 60 00:02:33,302 --> 00:02:38,571 So it'll be ten tens or a ten with a zero behind it. 61 00:02:38,571 --> 00:02:41,702 There you go. Notice, whatever number times ten, I just add a zero, 62 00:02:41,702 --> 00:02:42,725 then I get the next number. 63 00:02:42,725 --> 00:02:43,950 So it's one hundred. 64 00:02:43,960 --> 00:02:45,520 And I think you understand why that is. 65 00:02:45,530 --> 00:02:47,900 I added ten to itself ten times. 66 00:02:47,900 --> 00:02:51,700 That each ten-- you go from ten, twenty, thirty. 67 00:02:51,710 --> 00:02:54,240 Thirty is just three tens or ten times three. 68 00:02:54,250 --> 00:02:58,250 Ninety is just nine tens or nine times ten. 69 00:02:58,250 --> 00:03:00,450 Let's keep going. 70 00:03:00,460 --> 00:03:05,120 So ten times eleven is equal to eleven with a zero behind it. 71 00:03:05,120 --> 00:03:06,960 One hundred and ten. 72 00:03:06,960 --> 00:03:13,070 Finally, ten times twelve is equal to one hundred and twenty. 73 00:03:13,080 --> 00:03:17,370 Now, just for fun, these are kind of your ten times tables. 74 00:03:17,370 --> 00:03:20,460 But now that you know the pattern you can do anything. 75 00:03:20,470 --> 00:03:28,266 If I asked you what five thousand seven hundred thirty-two times ten is, 76 00:03:28,266 --> 00:03:29,691 what's it going to be? 77 00:03:29,691 --> 00:03:32,547 It's going to be this number with just one more zero. 78 00:03:32,547 --> 00:03:34,650 So it's going to be-- I won't read it out yet. 79 00:03:34,650 --> 00:03:39,080 Five seven three two with a zero behind it. 80 00:03:39,090 --> 00:03:40,122 And just so you know, 81 00:03:40,122 --> 00:03:42,445 this little comma that I wrote in the number there, 82 00:03:42,445 --> 00:03:45,882 that's just to make it easier for me to read that number. 83 00:03:45,882 --> 00:03:47,942 So, you put the comma-- you start over here 84 00:03:47,942 --> 00:03:49,740 and every third number you put the comma. 85 00:03:49,750 --> 00:03:53,080 So here I'm going to put the comma right here. 86 00:03:53,080 --> 00:03:54,960 I'm going to put the comma right there. 87 00:03:54,960 --> 00:03:56,640 So now I can read this. 88 00:03:56,650 --> 00:03:59,690 The comma doesn't really add or take anything away from the number, 89 00:03:59,690 --> 00:04:01,190 it just helps me read it. 90 00:04:01,190 --> 00:04:07,890 Now five thousand seven hundred thirty-two times ten is fifty-seven thousand three hundred twenty. 91 00:04:07,900 --> 00:04:09,195 I just had to add a zero there, 92 00:04:09,195 --> 00:04:12,708 but that was a pretty straightforward multiplication. 93 00:04:12,708 --> 00:04:15,239 And notice, we had five thousand times ten 94 00:04:15,239 --> 00:04:19,070 and we got to fifty-something thousand when we multiplied them. 95 00:04:19,070 --> 00:04:21,940 So that's similar to five times ten is equal to fifty. 96 00:04:21,950 --> 00:04:24,848 But instead of five I had a five thousand, 97 00:04:24,848 --> 00:04:28,050 and so I got a fifty thousand and something and all this other stuff. 98 00:04:28,060 --> 00:04:30,940 We're going to learn more about how to do problems like this in the future. 99 00:04:30,940 --> 00:04:32,512 But I thought I would introduce you to the idea 100 00:04:32,512 --> 00:04:34,922 that just from this little pattern of adding a zero, 101 00:04:34,922 --> 00:04:37,690 you already know your tens times tables. 102 00:04:37,690 --> 00:04:40,132 Now let's do our elevens. 103 00:04:40,132 --> 00:04:42,137 Our elevens, Elevens get a little bit-- 104 00:04:42,152 --> 00:04:43,224 Well, they start off easy, 105 00:04:43,224 --> 00:04:47,140 and then they get a little more difficult as we get into high numbers. 106 00:04:47,140 --> 00:04:49,000 So, eleven times zero. 107 00:04:49,000 --> 00:04:51,500 This is easy, this is zero! 108 00:04:51,510 --> 00:04:52,820 Eleven times one. 109 00:04:52,830 --> 00:04:54,000 This is also easy! 110 00:04:54,000 --> 00:04:56,000 It's eleven! 111 00:04:56,010 --> 00:04:57,350 Eleven times two. 112 00:04:57,360 --> 00:04:59,270 We're going to start seeing a pattern here. 113 00:04:59,270 --> 00:05:03,420 It's eleven plus eleven or we could've added two to itself eleven times, 114 00:05:03,430 --> 00:05:06,450 but that is equal to twenty-two. 115 00:05:06,450 --> 00:05:11,510 If we do eleven times three, it is equal to thirty-three. 116 00:05:11,510 --> 00:05:15,550 Eleven times four is equal to forty-four. 117 00:05:15,560 --> 00:05:16,970 I think this is becoming obvious to you. 118 00:05:16,970 --> 00:05:18,980 What's eleven times five? 119 00:05:18,990 --> 00:05:20,930 Eleven times five is fifty-five! 120 00:05:20,930 --> 00:05:23,000 Notice I put the five twice. 121 00:05:23,000 --> 00:05:24,930 What's eleven times six? 122 00:05:24,930 --> 00:05:27,320 It's sixty-six! 123 00:05:27,330 --> 00:05:30,820 Eleven times seven is eighty-four-- no! 124 00:05:30,830 --> 00:05:32,260 I'm kidding! 125 00:05:32,260 --> 00:05:33,710 I didn't want to mess with you like that. 126 00:05:33,720 --> 00:05:34,255 But no. 127 00:05:34,255 --> 00:05:36,910 Of course, it's seventy-seven! 128 00:05:36,910 --> 00:05:37,902 Seventy-seven. 129 00:05:37,902 --> 00:05:39,418 You just repeat the number twice. 130 00:05:39,418 --> 00:05:41,086 Seventy-seven. 131 00:05:41,086 --> 00:05:42,630 Let me switch colors. 132 00:05:42,630 --> 00:05:46,250 Eleven times eight is equal to eighty-eight. 133 00:05:46,260 --> 00:05:50,420 Eleven times nine is equal to ninety-nine! 134 00:05:50,420 --> 00:05:52,405 Now what's eleven times twelve? 135 00:05:52,405 --> 00:05:54,495 Eleven times twelve. 136 00:05:54,495 --> 00:05:56,728 Oh sorry, I skipped ten. 137 00:05:56,750 --> 00:05:58,140 Eleven times ten. 138 00:05:58,140 --> 00:06:00,150 You might want to say it's "tenty-ten!" 139 00:06:00,160 --> 00:06:00,720 No! 140 00:06:00,730 --> 00:06:01,410 That's wrong! 141 00:06:01,410 --> 00:06:05,090 It's not "tenty-ten!" 142 00:06:05,100 --> 00:06:06,844 So that little pattern that we had 143 00:06:06,844 --> 00:06:08,433 where you just repeat the number, 144 00:06:08,433 --> 00:06:10,056 that only works for one digit numbers. 145 00:06:10,056 --> 00:06:11,602 So it only works for one through nine. 146 00:06:11,602 --> 00:06:12,825 Eleven times ten-- 147 00:06:12,825 --> 00:06:14,570 well, we could think about it a couple of ways. 148 00:06:14,570 --> 00:06:16,740 We can add eleven to ninety-nine. 149 00:06:16,750 --> 00:06:20,873 So we can say it's ninety-nine plus eleven. 150 00:06:20,888 --> 00:06:21,995 And what's that? 151 00:06:21,995 --> 00:06:23,390 That's equal to one hundred and ten. 152 00:06:23,390 --> 00:06:24,809 And I'm going to show you how to do-- 153 00:06:24,809 --> 00:06:28,879 well, hopefully you've already watched the video on how to add two-digit numbers like this, 154 00:06:28,879 --> 00:06:30,210 but that's one hundred and ten. 155 00:06:30,220 --> 00:06:34,153 Or you could just use the property from the tens times tables that we learned. 156 00:06:34,157 --> 00:06:36,652 Where if you just take eleven times ten, you add a zero to the eleven, 157 00:06:36,652 --> 00:06:37,844 you get one hundred ten. 158 00:06:37,859 --> 00:06:39,590 That's the eleven right there. 159 00:06:39,590 --> 00:06:42,541 Finally, let's do eleven times twelve. 160 00:06:42,541 --> 00:06:44,694 Eleven times twelve. 161 00:06:44,694 --> 00:06:46,007 No easy way to remember this, 162 00:06:46,007 --> 00:06:47,080 you just kind of should remember it. 163 00:06:47,080 --> 00:06:48,180 Or you could say look, 164 00:06:48,180 --> 00:06:51,310 it's going to be eleven more than eleven times-- sorry. 165 00:06:51,310 --> 00:06:53,130 I keep skipping things. 166 00:06:53,140 --> 00:06:55,410 We should do eleven times eleven first. 167 00:06:55,420 --> 00:06:56,700 Let me make sure this is clear. 168 00:06:56,700 --> 00:07:00,590 We're doing eleven times eleven before we go to eleven times twelve. 169 00:07:00,600 --> 00:07:05,480 So eleven times eleven is going to be eleven more than eleven times ten. 170 00:07:05,490 --> 00:07:07,270 So we add eleven to this. 171 00:07:07,270 --> 00:07:13,120 Eleven plus one hundred ten is one hundred twenty-one. 172 00:07:13,120 --> 00:07:13,755 And actually, as you'll see, 173 00:07:13,755 --> 00:07:17,831 there actually is an order as we get to higher multiples of eleven, 174 00:07:17,846 --> 00:07:20,240 but I'll leave that to a future video. 175 00:07:20,250 --> 00:07:23,715 And then finally, we're at eleven times twelve. 176 00:07:23,715 --> 00:07:26,157 Eleven times twelve. 177 00:07:26,157 --> 00:07:28,552 And we could add eleven to itself twelve times. 178 00:07:28,552 --> 00:07:30,760 We could add twelve to itself eleven times. 179 00:07:30,760 --> 00:07:31,260 Or we could just say, 180 00:07:31,260 --> 00:07:37,910 hey, it's going to be eleven more than eleven times eleven. 181 00:07:37,910 --> 00:07:38,840 So that is what? 182 00:07:38,850 --> 00:07:40,800 You add eleven to this. 183 00:07:40,810 --> 00:07:41,350 What do you get? 184 00:07:41,350 --> 00:07:45,975 You get one hundred thirty-two. 185 00:07:45,975 --> 00:07:49,551 I just added one hundred twenty-one plus eleven 186 00:07:49,551 --> 00:07:50,998 and then got one hundred thirty-two. 187 00:07:50,998 --> 00:07:52,154 Now the other way you could have said it is, well, 188 00:07:52,154 --> 00:07:54,028 what's ten times twelve? 189 00:07:54,028 --> 00:07:54,987 Ten times twelve, 190 00:07:54,987 --> 00:07:56,160 we already knew that. 191 00:07:56,170 --> 00:07:58,570 That was one hundred twenty. 192 00:07:58,570 --> 00:08:00,888 So eleven times twelve, 193 00:08:00,888 --> 00:08:03,038 because we're multiplying twelve by one more 194 00:08:03,038 --> 00:08:04,933 should be twelve more than that. 195 00:08:04,933 --> 00:08:06,690 So that should be one hundred thirty-two. 196 00:08:06,700 --> 00:08:10,090 So two ways to get the exact same answer. 197 00:08:10,100 --> 00:08:14,118 All right! Now let's do our twelve times tables. 198 00:08:14,118 --> 00:08:15,173 Twelve times tables. 199 00:08:15,173 --> 00:08:16,378 And once you know this 200 00:08:16,378 --> 00:08:19,709 you are ready to tackle any type of multiplication problem. 201 00:08:19,709 --> 00:08:22,390 But we'll do that in future videos. 202 00:08:22,390 --> 00:08:23,983 So twelve times zero. 203 00:08:23,983 --> 00:08:25,575 Super easy! Zero. 204 00:08:25,575 --> 00:08:26,420 Twelve times one. 205 00:08:26,430 --> 00:08:27,330 Also super easy! 206 00:08:27,330 --> 00:08:28,480 Is twelve. 207 00:08:28,490 --> 00:08:29,920 Now it gets interesting. 208 00:08:29,930 --> 00:08:33,490 We're going to increase by twelve every time. 209 00:08:33,505 --> 00:08:37,160 Twelve times two is equal to twenty-four. 210 00:08:37,160 --> 00:08:40,041 Twelve plus twelve is twenty-four, right? 211 00:08:40,041 --> 00:08:43,230 Twelve times-- not twenty-two. 212 00:08:43,240 --> 00:08:44,160 Let me rewrite that. 213 00:08:44,160 --> 00:08:50,250 Twelve times three is going to be twelve plus twelve plus twelve. 214 00:08:50,250 --> 00:08:53,980 Or we could write that as twelve times two. 215 00:08:53,990 --> 00:08:56,070 I see my brain is doing the wrong things. 216 00:08:56,070 --> 00:09:00,670 We could rewrite that as twelve times two plus twelve. 217 00:09:00,670 --> 00:09:03,770 Or we could rewrite that as twenty-four plus twelve. 218 00:09:03,770 --> 00:09:07,020 Either way, all of these get us to thirty-six. 219 00:09:07,030 --> 00:09:10,400 And notice, that's just that plus twelve. 220 00:09:10,400 --> 00:09:12,240 Twelve times four. 221 00:09:12,250 --> 00:09:17,190 Twelve times four is equal to forty-eight. 222 00:09:17,190 --> 00:09:18,270 There's a lot of ways you could think about it. 223 00:09:18,270 --> 00:09:21,155 You could say eleven times four is forty-four. 224 00:09:21,155 --> 00:09:24,697 Right? Eleven times four is equal to forty-four. 225 00:09:24,697 --> 00:09:30,029 And you go up by one more four, so you get to twelve times four. 226 00:09:30,029 --> 00:09:32,851 Or you could say twelve times three is thirty-six 227 00:09:32,851 --> 00:09:36,940 and you can add one twelve to it to get to forty-eight. 228 00:09:36,950 --> 00:09:38,261 Either way works, 229 00:09:38,261 --> 00:09:40,300 and that's because you can multiply in either direction. 230 00:09:40,300 --> 00:09:42,300 Let's keep going. 231 00:09:42,300 --> 00:09:47,840 Twelve times five is equal to sixty. 232 00:09:47,850 --> 00:09:51,694 Ten times five is fifty, eleven times five is fifty-five, 233 00:09:51,694 --> 00:09:55,538 so twelve times five is sixty! 234 00:09:55,538 --> 00:09:59,014 Twelve times six is equal to what? 235 00:09:59,014 --> 00:10:00,570 It's going to be twelve more than this. 236 00:10:00,580 --> 00:10:02,630 It's going to be equal to seventy-two. 237 00:10:02,630 --> 00:10:04,515 Twelve times seven. 238 00:10:04,515 --> 00:10:06,710 Twelve more than this again. 239 00:10:06,720 --> 00:10:09,747 Twelve more than seventy-two is eighty-four. 240 00:10:09,747 --> 00:10:13,157 And I'm serious, you know, I'm probably a lot older than you are, 241 00:10:13,157 --> 00:10:17,262 and I still, in my head to confirm, 242 00:10:17,262 --> 00:10:20,700 I go to some twelve times tables that I remember as definitely right. 243 00:10:20,700 --> 00:10:23,018 Like oh, twelve times five-- and sometimes in my head I say, 244 00:10:23,018 --> 00:10:24,090 oh, let me add another twelve. 245 00:10:24,100 --> 00:10:26,290 Oh yeah, definitely, my memory was correct. 246 00:10:26,290 --> 00:10:28,480 Twelve times six is seventy-two. 247 00:10:28,490 --> 00:10:29,020 All right. 248 00:10:29,020 --> 00:10:31,320 Then you go to twelve times eight. 249 00:10:31,330 --> 00:10:33,685 Add twelve to the twelve times seven. 250 00:10:33,685 --> 00:10:35,400 Ninety-six. 251 00:10:35,400 --> 00:10:39,370 Twelve times nine. 252 00:10:39,370 --> 00:10:42,504 Well you add twelve to this, so it's one hundred eight. 253 00:10:42,504 --> 00:10:44,510 One hundred eight. 254 00:10:44,510 --> 00:10:46,700 And then twelve times ten. 255 00:10:46,700 --> 00:10:48,332 This is an easy one! 256 00:10:48,332 --> 00:10:51,380 Right? We just add a zero to the twelve to get one hundred twenty. 257 00:10:51,380 --> 00:10:54,200 Or we could've added twelve to one hundred eight. 258 00:10:54,210 --> 00:10:55,570 Either way. 259 00:10:55,570 --> 00:10:58,290 Twelve times eleven. 260 00:10:58,290 --> 00:10:59,406 We just did this. 261 00:10:59,406 --> 00:11:01,948 You add twelve to this to get one hundred thirty-two. 262 00:11:01,948 --> 00:11:05,077 And then twelve times twelve, 263 00:11:05,077 --> 00:11:08,931 is equal to one hundred forty-four. 264 00:11:08,931 --> 00:11:10,246 And this actually shows us-- 265 00:11:10,246 --> 00:11:13,777 If I had a dozen of a dozen eggs-- a dozen is twelve. 266 00:11:13,777 --> 00:11:17,010 Or if I had a-- I think a gross is actually twelve dozens. 267 00:11:17,010 --> 00:11:18,400 So that's one hundred forty-four eggs. 268 00:11:18,410 --> 00:11:20,700 So you'll actually end up seeing this number a lot. 269 00:11:20,710 --> 00:11:22,550 More than you would expect in life. 270 00:11:22,550 --> 00:11:27,402 But anyway, we've now completed all of our multiplication tables. 271 00:11:27,410 --> 00:11:30,918 And I really encourage you to take the time now to go and memorize them. 272 00:11:30,920 --> 00:11:32,538 Make some flash cards. 273 00:11:32,538 --> 00:11:37,100 Use the little software thing that I wrote on my website. 274 00:11:37,100 --> 00:11:38,850 You could try that out. 275 00:11:38,860 --> 00:11:41,730 As of September Two Thousand Nine, it's working. 276 00:11:41,730 --> 00:11:45,044 I haven't touched it in a while, but I'm actually probably going to rebuild it soon. 277 00:11:45,044 --> 00:11:48,117 So if you're watching this video in the year Two Thousand Two Hundred-- 278 00:11:48,117 --> 00:11:50,410 Well, I would probably not exist anymore. 279 00:11:50,420 --> 00:11:53,358 But hopefully you'll get a better version of the software app. 280 00:11:53,360 --> 00:11:55,020 But you should practice it. 281 00:11:55,020 --> 00:11:56,610 You should get your parents to quiz you. 282 00:11:56,620 --> 00:11:58,090 You should get notes cards. 283 00:11:58,090 --> 00:12:00,853 You should just be mumbling to yourself as you walk to school-- 284 00:12:00,853 --> 00:12:02,180 What is twelve times nine? 285 00:12:02,190 --> 00:12:03,740 What is eleven times eleven? 286 00:12:03,750 --> 00:12:05,305 And you should quiz each other, 287 00:12:05,305 --> 00:12:08,690 because it'll pay huge rewards to you later on in life. 288 00:12:08,690 --> 00:12:10,630 See you in the next video!