1 00:00:00,880 --> 00:00:05,805 現在我想你知道一點什麽是乘法 2 00:00:05,805 --> 00:00:09,025 現在我想你知道一點什麽是乘法 3 00:00:09,025 --> 00:00:13,315 在這個課程,我會給你很多很多的練習, 4 00:00:13,315 --> 00:00:17,706 也會幫你背熟你的乘法表。 5 00:00:17,706 --> 00:00:20,009 如果你看很多我的課程,你會知道,我不喜歡背熟東西。 6 00:00:20,009 --> 00:00:21,279 如果你看很多我的課程,你會知道,我不喜歡背熟東西。 7 00:00:21,279 --> 00:00:24,540 如果你看很多我的課程,你會知道,我不喜歡背熟東西。 8 00:00:24,550 --> 00:00:26,385 可是背熟乘法表,對你以後的人生會有很大的幫助。 9 00:00:26,385 --> 00:00:31,220 可是背熟乘法表,對你以後的人生會有很大的幫助。 10 00:00:31,220 --> 00:00:33,850 可是背熟乘法表,對你以後的人生會有很大的幫助。 11 00:00:33,850 --> 00:00:36,724 所以我保證,現在開始背乘法表,你將永遠不會忘記它。 12 00:00:36,724 --> 00:00:39,547 在你的余生,所有事情都會... 13 00:00:39,547 --> 00:00:41,517 好吧,我不想對你們做出錯誤的承諾。 14 00:00:41,517 --> 00:00:45,790 但是這比不背熟乘法表要好。 15 00:00:45,790 --> 00:00:47,290 所以,什麽是乘法表? 16 00:00:47,290 --> 00:00:49,745 乘法表是關於不同數字 17 00:00:49,745 --> 00:00:50,850 之間相乘的一張表。 18 00:00:50,850 --> 00:00:53,590 讓我們現在開始複習. 19 00:00:53,600 --> 00:00:58,900 2乘以1等於多少? 20 00:00:58,900 --> 00:01:02,270 這相當於2加上它自己本身一次。 21 00:01:02,280 --> 00:01:05,010 所以結果等於2 22 00:01:05,010 --> 00:01:07,060 這相當於2加上它自己本身一次。 23 00:01:07,060 --> 00:01:08,059 我不必加任何數 24 00:01:08,059 --> 00:01:09,430 因爲只有一個2,。 25 00:01:09,430 --> 00:01:13,460 我也可以把它當做1加自己兩次 26 00:01:13,460 --> 00:01:15,390 所以這也相當於1加1。 27 00:01:15,400 --> 00:01:17,580 結果仍然是2. 28 00:01:17,590 --> 00:01:18,210 好了。 29 00:01:18,210 --> 00:01:19,901 所以2乘以1等於2. 30 00:01:19,901 --> 00:01:22,722 如果你看了上一個影片,2乘以0等於多少? 31 00:01:22,722 --> 00:01:23,516 答案是0. 32 00:01:23,516 --> 00:01:26,660 所以你不必記住0的乘法表, 33 00:01:26,670 --> 00:01:30,560 因爲任何數乘以0都等於0,或者說0乘以任何數都等於0. 34 00:01:30,560 --> 00:01:31,090 我們來算一下, 35 00:01:31,090 --> 00:01:33,682 2乘以2等於多少? 36 00:01:33,682 --> 00:01:35,988 2乘以2 37 00:01:35,988 --> 00:01:37,254 它等於 38 00:01:37,254 --> 00:01:39,460 我們將要讓2加上它自身兩次。 39 00:01:39,460 --> 00:01:41,830 即2加2 40 00:01:41,840 --> 00:01:42,770 這只有一種方法, 41 00:01:42,780 --> 00:01:45,480 我可以說,用這個2再加上它自身 42 00:01:45,480 --> 00:01:46,680 但這其實是一回事。 43 00:01:46,680 --> 00:01:47,610 所以,2加2等於多少? 44 00:01:47,620 --> 00:01:49,450 等於4。 45 00:01:49,450 --> 00:01:51,400 2乘以3等於多少? 46 00:01:51,400 --> 00:01:57,900 2乘以3等於2加2加2。 47 00:01:57,900 --> 00:02:03,355 也可以等於3加3。 48 00:02:03,355 --> 00:02:04,905 我們從之前的影片中學到過, 49 00:02:04,920 --> 00:02:07,498 這個題目可以寫成這兩種形式中的任一種 50 00:02:07,498 --> 00:02:09,380 在任何一種情況下,答案等於多少? 51 00:02:09,397 --> 00:02:10,282 3加3 52 00:02:10,282 --> 00:02:12,028 等於2加2加2 53 00:02:12,028 --> 00:02:14,774 結果等於6 54 00:02:14,774 --> 00:02:15,812 好的。 55 00:02:15,812 --> 00:02:18,138 那麽2乘以4等於多少? 56 00:02:18,153 --> 00:02:20,686 2乘以4。 57 00:02:20,686 --> 00:02:26,065 等於2加2加2加2。 58 00:02:26,065 --> 00:02:29,870 請注意,這正相當於2乘以3。 59 00:02:29,870 --> 00:02:32,610 這些相當於2乘以3 60 00:02:32,620 --> 00:02:36,490 但是現在我又加了一個2 61 00:02:36,490 --> 00:02:39,740 所以如果我們不想計算2加2等於4。 62 00:02:39,740 --> 00:02:40,710 4加2等於6. 63 00:02:40,710 --> 00:02:41,802 我們可以說, 64 00:02:41,802 --> 00:02:45,680 瞧,我們已經知道答案了,這些等於6 65 00:02:45,680 --> 00:02:48,300 我們通過上一行算出來的。 66 00:02:48,310 --> 00:02:51,550 我們算出這些等於6,所以我們知道2乘以4 67 00:02:51,560 --> 00:02:55,610 比這些還要多2,所以結果等於8. 68 00:02:55,610 --> 00:02:57,480 這時,我希望你能看出規律。 69 00:02:57,490 --> 00:03:01,907 我們從2乘以1開始,到2乘以2, 70 00:03:01,907 --> 00:03:03,760 到2乘以3,發生什麽了? 71 00:03:03,770 --> 00:03:05,500 這些結果是以多少增長的? 72 00:03:05,500 --> 00:03:08,120 從2增長到到4,我們加2。 73 00:03:08,120 --> 00:03:11,300 從4增長到到6,我們加2。 74 00:03:11,310 --> 00:03:13,340 然後,從6增長到8,我們加2. 75 00:03:13,340 --> 00:03:15,685 所以你不用累加, 76 00:03:15,685 --> 00:03:16,950 便可以算出2乘以5等於多少。 77 00:03:16,960 --> 00:03:23,430 2加5等於2加2加2加2加2. 78 00:03:23,430 --> 00:03:26,070 也可以寫成5加5. 79 00:03:26,080 --> 00:03:29,110 2乘以4也可以寫成4加4. 80 00:03:29,120 --> 00:03:30,490 所以2乘以5等於幾? 81 00:03:30,500 --> 00:03:33,090 我們可以把這些都加起來,或者把這兩項加起來。 82 00:03:33,090 --> 00:03:36,285 或者我們可以理解爲比2乘以4還多2. 83 00:03:36,285 --> 00:03:38,564 所以答案是10. 84 00:03:38,564 --> 00:03:41,780 我將講解完2的乘法表。 85 00:03:41,780 --> 00:03:45,280 我想你已經看出了其中的規律。 86 00:03:45,280 --> 00:03:47,710 2乘以6, 87 00:03:47,710 --> 00:03:51,580 它等於2加它自身6次。 88 00:03:51,595 --> 00:03:55,369 1次,兩次,3次,4次,5次,6次, 89 00:03:55,369 --> 00:03:58,690 它也等於6加自身兩次。 90 00:03:58,690 --> 00:04:00,620 這可以被寫爲任何一種形式。 91 00:04:00,620 --> 00:04:02,980 結果等於12. 92 00:04:02,990 --> 00:04:06,898 再一次,也可看作比2乘以5多2 93 00:04:06,898 --> 00:04:09,710 因爲我們多加了一個2 94 00:04:09,710 --> 00:04:12,290 所以結果比10多了2. 95 00:04:12,300 --> 00:04:13,880 我們繼續。 96 00:04:13,880 --> 00:04:16,540 2乘以7。 97 00:04:16,550 --> 00:04:20,148 2乘以7等於-- 98 00:04:20,163 --> 00:04:24,104 我可以寫成2加2加2加2加2-- 99 00:04:24,104 --> 00:04:27,230 這寫起來很費勁--加2加2 100 00:04:27,240 --> 00:04:27,800 有7個2了嗎? 101 00:04:27,810 --> 00:04:31,200 1個,兩個,3個,4個,5個,6個,7個。 102 00:04:31,200 --> 00:04:33,849 這和7加7是一回事。 103 00:04:33,849 --> 00:04:37,370 不管你知不知道,答案等於14. 104 00:04:37,370 --> 00:04:39,550 你會發現,這比12多2. 105 00:04:39,560 --> 00:04:43,630 所以12加1加2等於--12加1等於13. 106 00:04:43,630 --> 00:04:45,530 12加2等於14. 107 00:04:45,540 --> 00:04:47,580 好的,我們繼續。 108 00:04:47,580 --> 00:04:50,740 2乘以8. 109 00:04:50,750 --> 00:04:53,810 我可以把所有2加起來 110 00:04:53,810 --> 00:04:56,660 或者我可以認爲,答案比2乘以7還多2. 111 00:04:56,670 --> 00:04:59,528 所以等於14加2 112 00:04:59,528 --> 00:05:00,470 我在這個數的基礎上加2. 113 00:05:00,480 --> 00:05:01,822 所以答案是16. 114 00:05:01,822 --> 00:05:05,610 或者可以看成8加8. 115 00:05:05,620 --> 00:05:06,800 答案仍然是16. 116 00:05:06,810 --> 00:05:08,174 我可以把所有的2寫出來, 117 00:05:08,174 --> 00:05:15,040 但是你可以自己做一下,這對你們的學習有好處。 118 00:05:15,040 --> 00:05:17,848 我們快結束了。其實,我們可以一直做下去。 119 00:05:17,848 --> 00:05:19,360 因爲不存在所謂的最大的數字。 120 00:05:19,370 --> 00:05:21,510 我可以繼續。 121 00:05:21,510 --> 00:05:24,970 2乘以9, 2乘以10,2乘以100,2乘以1000,2乘以1000000. 122 00:05:24,980 --> 00:05:26,642 但是我將乘到12爲止 123 00:05:26,642 --> 00:05:28,760 因爲這些是人們必須記住的。 124 00:05:28,770 --> 00:05:32,330 但是,如果你想成爲一個“數學計算家” 125 00:05:32,330 --> 00:05:34,260 你可以算到20. 126 00:05:34,260 --> 00:05:36,790 我們來計算2乘以9、 127 00:05:36,790 --> 00:05:38,810 它比2乘以8多2. 128 00:05:38,810 --> 00:05:40,990 所以答案是18。 129 00:05:40,990 --> 00:05:42,690 或者可以看成9加9, 130 00:05:42,690 --> 00:05:44,060 仍然等於18. 131 00:05:44,060 --> 00:05:45,930 2乘以10等於多少? 132 00:05:45,940 --> 00:05:47,940 10的乘法表比較有趣。 133 00:05:47,940 --> 00:05:49,550 當我們一會兒完成整個乘法表時, 134 00:05:49,560 --> 00:05:53,040 我們會看到其中的規律。 135 00:05:53,040 --> 00:05:54,640 2乘以10等於多少? 136 00:05:54,640 --> 00:05:56,800 比2乘以9還多2. 137 00:05:56,810 --> 00:05:59,050 答案是20。 138 00:05:59,050 --> 00:06:01,050 或者可看成10加10. 139 00:06:01,060 --> 00:06:03,360 10加上它自身兩次。 140 00:06:03,360 --> 00:06:05,060 現在,你發現了其中的奧妙了嗎? 141 00:06:05,060 --> 00:06:09,115 它看上去像是2後面加了一個0。 142 00:06:09,115 --> 00:06:10,690 而且,你會發現所有數字乘以10 143 00:06:10,690 --> 00:06:12,295 都等於在這個數字右邊加了一個0. 144 00:06:12,295 --> 00:06:14,130 你可以思考一下這是爲什麽。 145 00:06:14,130 --> 00:06:16,410 你可以把它看作兩個10,也就是20. 146 00:06:16,420 --> 00:06:18,000 這正是20的定義。 147 00:06:18,000 --> 00:06:19,540 我們快做完了。 148 00:06:19,550 --> 00:06:21,820 現在計算2乘以11. 149 00:06:21,820 --> 00:06:25,920 2乘以11比這個多2. 150 00:06:25,930 --> 00:06:27,830 答案是22. 151 00:06:27,830 --> 00:06:29,530 這又是一個有趣的規律。 152 00:06:29,540 --> 00:06:32,220 一個數字出現了兩遍--一個2,又一個2. 153 00:06:32,220 --> 00:06:33,160 很有趣。 154 00:06:33,170 --> 00:06:35,818 在我們學習其他數字的乘法表時 155 00:06:35,818 --> 00:06:38,690 我們應該注意其中的規律。 156 00:06:38,704 --> 00:06:40,140 最後, 157 00:06:40,140 --> 00:06:42,129 這不是最後,我們可以一直繼續, 158 00:06:42,129 --> 00:06:44,682 2乘以……字的顏色太深了。 159 00:06:44,682 --> 00:06:47,059 2乘以12. 160 00:06:47,059 --> 00:06:50,540 2乘以12比2乘以11還多2. 161 00:06:50,550 --> 00:06:51,826 結果是24. 162 00:06:51,826 --> 00:06:54,160 我們也可以寫成12加12. 163 00:06:54,170 --> 00:06:56,110 或者也可以寫成2加2加2 164 00:06:56,110 --> 00:06:57,840 加2……一共12次。 165 00:06:57,850 --> 00:06:59,660 答案都能算出來24. 166 00:06:59,670 --> 00:07:00,961 這就是2的乘法表 167 00:07:00,961 --> 00:07:01,970 我認爲你們應該看出了其中的規律。 168 00:07:01,980 --> 00:07:04,755 每當你用一個更大的數乘以2, 169 00:07:04,755 --> 00:07:06,670 你就在那個數的基礎了又加了一個2. 170 00:07:06,680 --> 00:07:08,748 現在,我們找到了其中的規律。 171 00:07:08,748 --> 00:07:11,950 現在我們嘗試一下是否可以完成乘法表。 172 00:07:11,950 --> 00:07:16,260 現在我想寫下所有的數字。 173 00:07:16,270 --> 00:07:18,485 我們來看一下。 174 00:07:18,485 --> 00:07:19,361 我希望我能寫的下。 175 00:07:19,361 --> 00:07:29,430 1,2,3,4,5,6,7,8,9。 176 00:07:29,430 --> 00:07:30,910 實際上,我要從9做起。 177 00:07:30,920 --> 00:07:31,830 我要繼續寫下去。 178 00:07:31,830 --> 00:07:32,970 9。 179 00:07:32,970 --> 00:07:34,106 但是我寫不下了 180 00:07:34,106 --> 00:07:35,680 因爲我想讓你們看見完整的乘法表。 181 00:07:35,680 --> 00:07:37,045 所以我只能做到9. 182 00:07:37,045 --> 00:07:39,590 但我鼓勵你們看完這個影片後自己完成。 183 00:07:39,600 --> 00:07:42,880 如果有時間的話,我也會在這把乘法表完成。 184 00:07:42,880 --> 00:07:45,887 這些是我想乘的第一個數字。 185 00:07:45,887 --> 00:07:52,060 我想用它們乘以1,2,3,4 186 00:07:52,060 --> 00:07:57,650 5,6,7,8和9. 187 00:07:57,650 --> 00:08:00,183 我要開始做了。 188 00:08:00,183 --> 00:08:01,298 首先, 189 00:08:01,298 --> 00:08:03,321 其實我應該把這個1寫在下面-- 190 00:08:03,321 --> 00:08:04,710 1乘以1等於多少? 191 00:08:04,720 --> 00:08:06,110 這正是我想要呈現的效果。 192 00:08:06,120 --> 00:08:08,730 1乘以1的結果我寫在這。 193 00:08:08,730 --> 00:08:09,970 等於1. 194 00:08:09,970 --> 00:08:11,510 1乘以2等於多少? 195 00:08:11,510 --> 00:08:12,400 等於2. 196 00:08:12,410 --> 00:08:13,730 1乘以3呢? 197 00:08:13,740 --> 00:08:14,360 等於3. 198 00:08:14,360 --> 00:08:15,866 1乘以任何數就等於那個數本身。 199 00:08:15,866 --> 00:08:21,360 所以我可以寫下4,5,6,7,8,9. 200 00:08:21,370 --> 00:08:23,540 1乘以9等於9. 201 00:08:23,540 --> 00:08:24,540 好了。 202 00:08:24,540 --> 00:08:26,300 現在做2的乘法表。 203 00:08:26,310 --> 00:08:27,570 我用藍色筆寫。 204 00:08:27,570 --> 00:08:30,270 我們用這種顏色做1的乘法表. 205 00:08:30,285 --> 00:08:33,980 用這個深藍色做2的乘法表。 206 00:08:33,990 --> 00:08:35,250 2乘以1等於多少? 207 00:08:35,250 --> 00:08:36,430 等於2. 208 00:08:36,440 --> 00:08:37,690 它和1乘以2一樣。 209 00:08:37,700 --> 00:08:40,000 注意,這兩個數字是一樣的。 210 00:08:40,000 --> 00:08:41,700 2乘以2等於多少? 211 00:08:41,710 --> 00:08:43,000 等於4 212 00:08:43,000 --> 00:08:44,610 2乘以3等於6. 213 00:08:44,620 --> 00:08:45,840 我們剛才算了這個。 214 00:08:45,840 --> 00:08:49,821 每次增加或乘以一個更大的數, 215 00:08:49,821 --> 00:08:51,190 我們只要加上2即可。 216 00:08:51,190 --> 00:08:52,840 2乘以4等於8. 217 00:08:52,850 --> 00:08:55,110 相當於4乘以2. 218 00:08:55,120 --> 00:08:57,260 2乘以5等於10. 219 00:08:57,260 --> 00:08:59,010 2乘以6等於12. 220 00:08:59,010 --> 00:09:00,660 我每次都加2. 221 00:09:00,670 --> 00:09:03,970 在上面這行,我每步都加上1.在這行,我們每次都加上2. 222 00:09:03,980 --> 00:09:06,830 2乘以7等於14. 223 00:09:06,830 --> 00:09:09,813 2乘以8等於16. 224 00:09:09,813 --> 00:09:12,970 2乘以9等於18. 225 00:09:12,980 --> 00:09:17,789 好了。現在來做3的乘法表。 226 00:09:17,789 --> 00:09:20,508 我用黃色筆寫。 227 00:09:20,508 --> 00:09:21,783 我用黃色筆寫。 228 00:09:21,783 --> 00:09:23,828 2乘以1等於3. 229 00:09:23,828 --> 00:09:25,350 注意,3乘以1等於3. 230 00:09:25,360 --> 00:09:26,910 1乘以3也等於3. 231 00:09:26,910 --> 00:09:28,740 它們答案是一樣的。 232 00:09:28,750 --> 00:09:32,158 3乘以2等於2乘以3. 233 00:09:32,158 --> 00:09:37,640 3乘以2和2乘以3是一回事。 234 00:09:37,640 --> 00:09:39,680 結果是6. 235 00:09:39,690 --> 00:09:40,485 這有點意思。 236 00:09:40,485 --> 00:09:45,690 3加3等於6,2加2加2也等於6. 237 00:09:45,690 --> 00:09:47,780 所以,我們每次都以3增長。 238 00:09:47,780 --> 00:09:48,880 你可以發現其中的規律。 239 00:09:48,880 --> 00:09:51,000 3乘以3等於9。 240 00:09:51,010 --> 00:09:52,852 相當於3加3加3. 241 00:09:52,852 --> 00:09:54,725 我們從3增長到6,6又增長到9. 242 00:09:54,736 --> 00:09:57,001 所以,3乘以4等於12. 243 00:09:57,001 --> 00:09:58,850 我每次都加了3. 244 00:09:58,850 --> 00:10:00,642 12加3等於15. 245 00:10:00,642 --> 00:10:03,404 15加3等於18. 246 00:10:03,404 --> 00:10:05,580 18加3等於21. 247 00:10:05,580 --> 00:10:08,080 21加3等於24. 248 00:10:08,090 --> 00:10:10,500 24加3等於27. 249 00:10:10,500 --> 00:10:13,110 所以3乘以9等於27. 250 00:10:13,120 --> 00:10:14,840 3乘以8等於24. 251 00:10:14,840 --> 00:10:19,094 所以你也可以看成是8加8加8,結果是24. 252 00:10:19,094 --> 00:10:20,180 現在我想 253 00:10:20,180 --> 00:10:21,544 加快一點速度, 254 00:10:21,544 --> 00:10:22,830 因爲我們已經找到了規律。 255 00:10:22,840 --> 00:10:24,088 你應該自己完成這些 256 00:10:24,088 --> 00:10:26,970 並且記住我們正在做的這些。 257 00:10:26,980 --> 00:10:30,495 你應該從兩個方向都計算到12。 258 00:10:30,495 --> 00:10:31,057 讓我們來看看。 259 00:10:31,057 --> 00:10:35,330 4乘以1等於4. 260 00:10:35,330 --> 00:10:37,640 我將以4爲增量遞增計算。 261 00:10:37,640 --> 00:10:40,080 4加4等於8. 262 00:10:40,090 --> 00:10:41,960 8加4等於12. 263 00:10:41,970 --> 00:10:43,920 12加4等於16. 264 00:10:43,920 --> 00:10:46,450 16加4等於20. 265 00:10:46,460 --> 00:10:48,460 20加4等於24. 266 00:10:48,460 --> 00:10:51,460 4乘以6等於24. 267 00:10:51,470 --> 00:10:52,970 4乘以7等於28. 268 00:10:52,980 --> 00:10:54,250 我每次都加4. 269 00:10:54,250 --> 00:10:58,740 後面兩個結果是32和36. 270 00:10:58,750 --> 00:11:01,490 好的,5乘以1. 271 00:11:01,490 --> 00:11:06,670 5乘以1等於5. 272 00:11:06,670 --> 00:11:09,565 其實,我想一直變換顏色, 273 00:11:09,565 --> 00:11:11,400 所以我要像這樣一排一排的寫。 274 00:11:11,410 --> 00:11:12,570 5乘以1等於5. 275 00:11:12,580 --> 00:11:15,780 5乘以2等於10. 276 00:11:15,780 --> 00:11:17,260 5乘以3等於15. 277 00:11:17,260 --> 00:11:18,430 我將以5爲增量遞增。 278 00:11:18,440 --> 00:11:20,687 5的乘法表也十分有趣。 279 00:11:20,687 --> 00:11:24,120 因爲你加上的每一個數字,如果我們乘5次, 280 00:11:24,120 --> 00:11:25,870 我們以後將會學到偶數和奇數。 281 00:11:25,880 --> 00:11:30,241 但是這個乘法表裏的每一些數字都以5結尾, 282 00:11:30,241 --> 00:11:32,240 而另一些數字都以0結尾。 283 00:11:32,250 --> 00:11:34,790 因爲,如果你在15的基礎上加5,結果是20. 284 00:11:34,790 --> 00:11:41,871 接著是25,30,35,40,45. 285 00:11:41,871 --> 00:11:43,380 好了。 286 00:11:43,380 --> 00:11:47,120 我們用綠色的筆寫6的乘法表。 287 00:11:47,120 --> 00:11:48,210 6乘以1等於6. 288 00:11:48,220 --> 00:11:49,080 這很簡單。 289 00:11:49,080 --> 00:11:50,800 再加上6,答案是12. 290 00:11:50,800 --> 00:11:52,490 再加上6,答案是18. 291 00:11:52,500 --> 00:11:54,250 再加上6,答案是24. 292 00:11:54,250 --> 00:11:56,220 再加上6,答案是30. 293 00:11:56,220 --> 00:12:01,220 再加上6,得到36,42,48. 294 00:12:01,220 --> 00:12:04,620 48加6等於54. 295 00:12:04,620 --> 00:12:07,620 所以,6乘以9等於54. 296 00:12:07,620 --> 00:12:08,990 我們快完成了。 297 00:12:09,000 --> 00:12:11,610 7乘以1等於7. 298 00:12:11,620 --> 00:12:13,520 7乘以1等於7. 299 00:12:13,520 --> 00:12:15,610 7乘以2等於14. 300 00:12:15,620 --> 00:12:17,740 7乘以3等於21. 301 00:12:17,740 --> 00:12:20,040 7乘以4等於28. 302 00:12:20,040 --> 00:12:23,512 7乘以5,28加7等於多少? 303 00:12:23,512 --> 00:12:25,130 28加2等於30. 304 00:12:25,130 --> 00:12:27,700 然後再加上5,答案是35. 305 00:12:27,710 --> 00:12:29,480 7乘以6等於42. 306 00:12:29,490 --> 00:12:32,640 7乘以7等於49. 307 00:12:32,640 --> 00:12:34,775 7乘以8 308 00:12:34,775 --> 00:12:37,830 等於7加上這個,等於56. 309 00:12:37,830 --> 00:12:41,580 我經常在7乘以8等於56 310 00:12:41,590 --> 00:12:43,610 和6乘以9等於54中間弄混。 311 00:12:43,620 --> 00:12:46,705 所以現在我提醒你們,我經常弄混這兩個數, 312 00:12:46,705 --> 00:12:49,389 而你們不應該被這兩個數弄混。 313 00:12:49,390 --> 00:12:52,610 你可以認爲7乘以8裏面有個6, 314 00:12:52,620 --> 00:12:54,850 而6乘以9裏面沒有6. 315 00:12:54,850 --> 00:12:56,080 這是我記住它們的方法。 316 00:12:56,080 --> 00:12:57,580 7乘以9, 317 00:12:57,580 --> 00:12:59,320 我們再加上一個7, 318 00:12:59,320 --> 00:13:01,152 結果是63. 319 00:13:01,152 --> 00:13:04,830 我用一樣的顏色寫。 320 00:13:04,840 --> 00:13:08,350 好的。現在是8的乘法表。 321 00:13:08,360 --> 00:13:10,660 8乘以1等於8. 322 00:13:10,660 --> 00:13:12,520 8乘以2等於16. 323 00:13:12,520 --> 00:13:14,090 24. 324 00:13:14,100 --> 00:13:15,690 8乘以3等於24. 325 00:13:15,690 --> 00:13:18,300 如果我們計算3乘以8,結果仍然是24. 326 00:13:18,300 --> 00:13:19,500 對,在那呢。 327 00:13:19,500 --> 00:13:21,110 這兩個數相等。 328 00:13:21,120 --> 00:13:22,800 所以我們實際上算了兩遍。 329 00:13:22,800 --> 00:13:24,848 在算8乘以3時 330 00:13:24,848 --> 00:13:27,470 和3乘以8時,我們都計算了它。 331 00:13:27,472 --> 00:13:31,210 8乘以4,在前面的數字上再加上8,等於32. 332 00:13:31,220 --> 00:13:32,480 40. 333 00:13:32,490 --> 00:13:34,690 再加8,48. 334 00:13:34,690 --> 00:13:37,270 注意,8乘以6等於48. 335 00:13:37,270 --> 00:13:40,230 6乘以8也等於48. 336 00:13:40,240 --> 00:13:42,450 8乘以7, 337 00:13:42,450 --> 00:13:45,860 我們已經標出了,等於56. 338 00:13:45,870 --> 00:13:48,200 8乘以8等於64. 339 00:13:48,200 --> 00:13:52,010 8乘以9,在這個數上面加8,等於72. 340 00:13:52,010 --> 00:13:54,640 現在來計算9的乘法表。 341 00:13:54,650 --> 00:13:57,260 筆顏色用完了。 342 00:13:57,260 --> 00:13:59,520 我可能會重覆用一種或兩種顏色。 343 00:13:59,530 --> 00:14:01,100 我再用藍色。 344 00:14:01,110 --> 00:14:03,280 9乘以1等於9. 345 00:14:03,280 --> 00:14:06,700 9乘以2等於18. 9乘以3--實際上我們已經知道了答案。 346 00:14:06,710 --> 00:14:08,097 我們可以在表中的其他數字找到答案。 347 00:14:08,097 --> 00:14:11,290 因爲9乘以3等於3乘以9. 348 00:14:11,290 --> 00:14:13,280 結果是27. 349 00:14:13,280 --> 00:14:14,500 再加上9。 350 00:14:14,500 --> 00:14:18,380 27加9等於36. 351 00:14:18,390 --> 00:14:21,520 36加9等於45. 352 00:14:21,530 --> 00:14:25,331 注意,每次加9,結果將近加了10, 353 00:14:25,331 --> 00:14:26,219 但比10少1. 354 00:14:26,219 --> 00:14:29,970 所以36加10等於46,再減1,結果是45. 355 00:14:29,970 --> 00:14:32,647 注意,這些 356 00:14:32,647 --> 00:14:33,880 我以後會說到。 357 00:14:33,890 --> 00:14:37,510 但是在這一位上,即第二位上 358 00:14:37,520 --> 00:14:38,835 數字從9到8到7到6到5, 359 00:14:38,835 --> 00:14:42,510 並且在這一位上,是1,2,3,4。 360 00:14:42,510 --> 00:14:44,010 這又是個有趣的規律。 361 00:14:44,020 --> 00:14:47,240 另一個有趣的規律是,兩個數位上的數字加起來等於9. 362 00:14:47,250 --> 00:14:49,270 3加6等於9,2加7等於9. 363 00:14:49,270 --> 00:14:50,831 我們以後會討論並且證明這個問題。 364 00:14:50,831 --> 00:14:52,620 我們以後會討論並且證明這個問題。 365 00:14:52,630 --> 00:14:56,340 9乘以6等於54. 366 00:14:56,350 --> 00:14:58,150 它等於這個數。 367 00:14:58,150 --> 00:15:01,720 9乘以7等於63. 368 00:15:01,730 --> 00:15:03,850 9乘以8等於72. 369 00:15:03,860 --> 00:15:05,910 9乘以9等於81. 370 00:15:05,910 --> 00:15:07,030 不知道你們看不看的到。 371 00:15:07,040 --> 00:15:08,360 等於81。 372 00:15:08,370 --> 00:15:09,480 現在完成了。 373 00:15:09,480 --> 00:15:11,080 現在,我可以繼續寫下去。 374 00:15:11,080 --> 00:15:13,780 其實,我也應該繼續寫下去。 375 00:15:13,780 --> 00:15:17,525 但是,我意識到這段影片已經很長了。 376 00:15:17,525 --> 00:15:19,316 我希望你們現在就能記住這些 377 00:15:19,316 --> 00:15:21,200 因爲這些在以後的學習中很有用。 378 00:15:21,210 --> 00:15:25,542 我將會在下段影片中完成9以後的乘法表。 379 00:15:25,542 --> 00:15:26,960 下次見!