[Script Info] Title: [Events] Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text Dialogue: 0,0:00:00.81,0:00:03.11,Default,,0000,0000,0000,,歡迎來到分數除法的教學課程 Dialogue: 0,0:00:03.11,0:00:04.49,Default,,0000,0000,0000,,讓我們開始吧 Dialogue: 0,0:00:04.49,0:00:06.64,Default,,0000,0000,0000,,在我教你們之前,事實上,我想要 Dialogue: 0,0:00:06.64,0:00:09.34,Default,,0000,0000,0000,,用不同的模組來教--我將教你 Dialogue: 0,0:00:09.34,0:00:11.74,Default,,0000,0000,0000,,如何做分數除法的技巧 Dialogue: 0,0:00:11.74,0:00:13.74,Default,,0000,0000,0000,,而你會發現這其實 Dialogue: 0,0:00:13.74,0:00:16.03,Default,,0000,0000,0000,,不會比分數乘法更難 Dialogue: 0,0:00:16.03,0:00:21.41,Default,,0000,0000,0000,,如果我問你,1/2除以1/2,不論何時 Dialogue: 0,0:00:21.41,0:00:25.11,Default,,0000,0000,0000,,當數字除以分數,或除以任何數字的時候 Dialogue: 0,0:00:25.11,0:00:29.96,Default,,0000,0000,0000,,就等於乘以這個數字的倒數 Dialogue: 0,0:00:29.96,0:00:36.67,Default,,0000,0000,0000,,所以,1/2除以1/2,就等於1/2乘以2/1 Dialogue: 0,0:00:36.67,0:00:44.99,Default,,0000,0000,0000,,我們剛剛把第二個1/2變為倒數 Dialogue: 0,0:00:44.99,0:00:47.63,Default,,0000,0000,0000,,我們從乘法模組知道,1/2乘以2/1 Dialogue: 0,0:00:47.63,0:00:51.11,Default,,0000,0000,0000,,就等於2/2 Dialogue: 0,0:00:51.11,0:00:53.56,Default,,0000,0000,0000,,或者就等於1 Dialogue: 0,0:00:53.56,0:00:56.02,Default,,0000,0000,0000,,這很合理,事實上,任何數字除以自己 Dialogue: 0,0:00:56.02,0:00:58.75,Default,,0000,0000,0000,,就等於1 Dialogue: 0,0:00:58.75,0:01:03.22,Default,,0000,0000,0000,,1/2除以1/2等於1,就像是5除以5等於1 Dialogue: 0,0:01:03.22,0:01:05.24,Default,,0000,0000,0000,,100除以100等於1 Dialogue: 0,0:01:05.24,0:01:06.85,Default,,0000,0000,0000,,這不是一個新的定律 Dialogue: 0,0:01:06.85,0:01:08.97,Default,,0000,0000,0000,,事實上,你過去總是如此做 Dialogue: 0,0:01:16.29,0:01:20.56,Default,,0000,0000,0000,,例如2除以2,你知道是1,但這不就像是2乘以2的倒數 Dialogue: 0,0:01:20.56,0:01:24.21,Default,,0000,0000,0000,,結果也是1 Dialogue: 0,0:01:24.21,0:01:24.95,Default,,0000,0000,0000,,我將演示給你看 Dialogue: 0,0:01:24.95,0:01:26.99,Default,,0000,0000,0000,,事實上,讓我多秀幾個例子 Dialogue: 0,0:01:26.99,0:01:31.34,Default,,0000,0000,0000,,讓你了解分數除法真的不是個新的觀念 Dialogue: 0,0:01:31.34,0:01:34.84,Default,,0000,0000,0000,,整個概念就是乘以它的倒數 Dialogue: 0,0:01:34.84,0:01:40.54,Default,,0000,0000,0000,,如果我問你12除以4是多少? Dialogue: 0,0:01:40.54,0:01:42.65,Default,,0000,0000,0000,,當然我們知道答案是什麼,但是我要 Dialogue: 0,0:01:42.65,0:01:50.64,Default,,0000,0000,0000,,演示給你看,其實這跟12乘以1/4是一樣的 Dialogue: 0,0:01:50.64,0:01:56.23,Default,,0000,0000,0000,,12/1乘以1/4等於12/4,等於3 Dialogue: 0,0:01:56.23,0:01:59.48,Default,,0000,0000,0000,,而12/4就是12除以4的另一種書寫方式 Dialogue: 0,0:01:59.48,0:02:02.54,Default,,0000,0000,0000,,這就有點像是用比較複雜的方法來得到一樣的結果 Dialogue: 0,0:02:02.54,0:02:04.99,Default,,0000,0000,0000,,但是,我只是想讓你知道我們正在做的 Dialogue: 0,0:02:04.99,0:02:07.97,Default,,0000,0000,0000,,這個模組不是新的,其實就像是我們過去一直在做的 Dialogue: 0,0:02:07.97,0:02:09.32,Default,,0000,0000,0000,,當我們除以一個數字 Dialogue: 0,0:02:09.32,0:02:11.36,Default,,0000,0000,0000,,除法都是一樣的 Dialogue: 0,0:02:11.36,0:02:14.31,Default,,0000,0000,0000,,當除以一個數字,其實就等同於乘以 Dialogue: 0,0:02:14.31,0:02:15.96,Default,,0000,0000,0000,,那個數字的倒數 Dialogue: 0,0:02:15.96,0:02:19.88,Default,,0000,0000,0000,,復習一下倒數,當我有一個數字A Dialogue: 0,0:02:19.88,0:02:28.07,Default,,0000,0000,0000,,它的倒數--就是1/A Dialogue: 0,0:02:28.07,0:02:36.29,Default,,0000,0000,0000,,所以2/3的倒數是3/2,或者5的倒數 Dialogue: 0,0:02:36.29,0:02:39.67,Default,,0000,0000,0000,,因為5就等於5/1,所以5的倒數是1/5 Dialogue: 0,0:02:43.32,0:02:46.48,Default,,0000,0000,0000,,讓我們來做一些分數除法的問題吧 Dialogue: 0,0:02:46.48,0:02:49.27,Default,,0000,0000,0000,,2/3除以5/6是多少? Dialogue: 0,0:02:56.34,0:03:05.97,Default,,0000,0000,0000,,我們知道,這就等同於2/3乘以6/5 Dialogue: 0,0:03:05.97,0:03:09.23,Default,,0000,0000,0000,,就等於12/15 Dialogue: 0,0:03:09.23,0:03:14.57,Default,,0000,0000,0000,,我們可以把分子及分母同時除以3,就等於4/5 Dialogue: 0,0:03:14.57,0:03:22.90,Default,,0000,0000,0000,,7/8除以1/4等於多少? Dialogue: 0,0:03:22.90,0:03:30.52,Default,,0000,0000,0000,,這就等同於7/8乘以4/1 Dialogue: 0,0:03:30.52,0:03:32.82,Default,,0000,0000,0000,,記住,我剛剛翻轉了1/4 Dialogue: 0,0:03:32.82,0:03:36.84,Default,,0000,0000,0000,,除以1/4就等同於乘以4/1 Dialogue: 0,0:03:36.84,0:03:38.23,Default,,0000,0000,0000,,這就是你要解答分數除法的方式 Dialogue: 0,0:03:38.23,0:03:39.99,Default,,0000,0000,0000,,接著我們可以用一些在乘法模組 Dialogue: 0,0:03:39.99,0:03:41.48,Default,,0000,0000,0000,,學到的小捷徑 Dialogue: 0,0:03:41.48,0:03:42.95,Default,,0000,0000,0000,,8除以4等於2 Dialogue: 0,0:03:42.95,0:03:44.80,Default,,0000,0000,0000,,4除以4等於1 Dialogue: 0,0:03:44.80,0:03:47.45,Default,,0000,0000,0000,,所以答案就是7/2 Dialogue: 0,0:03:47.45,0:03:49.90,Default,,0000,0000,0000,,或者如果你想要把它寫成帶分數 Dialogue: 0,0:03:49.90,0:03:51.20,Default,,0000,0000,0000,,7/2是一個假分數 Dialogue: 0,0:03:51.20,0:03:53.44,Default,,0000,0000,0000,,假分數,它的分子 Dialogue: 0,0:03:53.44,0:03:54.83,Default,,0000,0000,0000,,會大於分母 Dialogue: 0,0:03:54.83,0:03:58.67,Default,,0000,0000,0000,,如果你想要把它寫成帶分數 Dialogue: 0,0:03:58.67,0:04:03.68,Default,,0000,0000,0000,,7除2等於3餘1,所以就是3 1/2 Dialogue: 0,0:04:03.68,0:04:04.44,Default,,0000,0000,0000,,兩種方式都可以 Dialogue: 0,0:04:04.44,0:04:05.99,Default,,0000,0000,0000,,我比較傾向用這個方式 Dialogue: 0,0:04:05.99,0:04:07.80,Default,,0000,0000,0000,,因為它比較容易做計算 Dialogue: 0,0:04:07.80,0:04:10.13,Default,,0000,0000,0000,,讓我們再多做幾題,或者是至少在接下來4~5分鐘裡面 Dialogue: 0,0:04:10.13,0:04:13.83,Default,,0000,0000,0000,,可以盡量多做一些 Dialogue: 0,0:04:13.83,0:04:23.85,Default,,0000,0000,0000,,-2/3除以5/2等於多少 Dialogue: 0,0:04:23.85,0:04:29.11,Default,,0000,0000,0000,,再一次,這就等於-2/3 Dialogue: 0,0:04:29.11,0:04:34.85,Default,,0000,0000,0000,,乘以多少? Dialogue: 0,0:04:34.85,0:04:40.11,Default,,0000,0000,0000,,就等於乘以5/2的倒數,就是2/5 Dialogue: 0,0:04:40.11,0:04:45.63,Default,,0000,0000,0000,,所以就等於-4/15 Dialogue: 0,0:04:45.63,0:04:52.30,Default,,0000,0000,0000,,3/2除以1/6等於多少? Dialogue: 0,0:04:52.30,0:04:59.85,Default,,0000,0000,0000,,這就等於3/2乘以6/1,就等於9 Dialogue: 0,0:05:09.61,0:05:11.28,Default,,0000,0000,0000,,我想你現在可能已經了解了 Dialogue: 0,0:05:11.28,0:05:12.95,Default,,0000,0000,0000,,讓我們看看,再多做幾題 Dialogue: 0,0:05:12.95,0:05:16.29,Default,,0000,0000,0000,,當然,你可以隨時暫停,再重新看一次這個課程 Dialogue: 0,0:05:16.29,0:05:19.42,Default,,0000,0000,0000,,然後再把看不懂的地方重看一遍 Dialogue: 0,0:05:19.42,0:05:27.24,Default,,0000,0000,0000,,讓我們來做 -5/7除以10/3 Dialogue: 0,0:05:27.24,0:05:33.88,Default,,0000,0000,0000,,這就等同於-5/7乘以3/10 Dialogue: 0,0:05:33.88,0:05:35.42,Default,,0000,0000,0000,,我剛剛把它乘以倒數 Dialogue: 0,0:05:35.42,0:05:38.12,Default,,0000,0000,0000,,這就是我剛剛一直重覆在做的 Dialogue: 0,0:05:38.12,0:05:40.18,Default,,0000,0000,0000,,-5乘以3 Dialogue: 0,0:05:40.18,0:05:42.61,Default,,0000,0000,0000,,-15 Dialogue: 0,0:05:42.61,0:05:47.35,Default,,0000,0000,0000,,7乘以10等於70 Dialogue: 0,0:05:47.35,0:05:49.90,Default,,0000,0000,0000,,如果我們把分子及分母 Dialogue: 0,0:05:49.90,0:05:56.05,Default,,0000,0000,0000,,同除以5,我們可以得到 -3/14 Dialogue: 0,0:05:56.05,0:05:57.50,Default,,0000,0000,0000,,我們也可以在這邊就這樣做 Dialogue: 0,0:05:57.50,0:05:59.89,Default,,0000,0000,0000,,我們可以除以5,得到2,同樣可以得到 Dialogue: 0,0:05:59.89,0:06:02.51,Default,,0000,0000,0000,,-3/14 Dialogue: 0,0:06:02.51,0:06:05.42,Default,,0000,0000,0000,,讓我們再做一兩個題目 Dialogue: 0,0:06:05.42,0:06:06.63,Default,,0000,0000,0000,,我想你已經有點了解了 Dialogue: 0,0:06:06.63,0:06:09.60,Default,,0000,0000,0000,,如果1/2除以-3 Dialogue: 0,0:06:14.50,0:06:14.96,Default,,0000,0000,0000,,啊哈 Dialogue: 0,0:06:14.96,0:06:17.94,Default,,0000,0000,0000,,所以,當一個分數除以一個正整數 Dialogue: 0,0:06:17.94,0:06:19.73,Default,,0000,0000,0000,,或者整數時會如何呢? Dialogue: 0,0:06:19.73,0:06:22.97,Default,,0000,0000,0000,,我們知道任何正整數可以被寫做分數 Dialogue: 0,0:06:22.97,0:06:29.01,Default,,0000,0000,0000,,這就等於1/2除以-3/1 Dialogue: 0,0:06:29.01,0:06:33.87,Default,,0000,0000,0000,,而除以一個分數就等同於乘以 Dialogue: 0,0:06:33.87,0:06:37.43,Default,,0000,0000,0000,,它的倒數 Dialogue: 0,0:06:37.43,0:06:42.15,Default,,0000,0000,0000,,所以-3/1的倒數是-1/3 Dialogue: 0,0:06:42.15,0:06:45.20,Default,,0000,0000,0000,,所以就等於-1/6 Dialogue: 0,0:06:45.20,0:06:46.04,Default,,0000,0000,0000,,讓我們換個方式做 Dialogue: 0,0:06:46.04,0:06:51.88,Default,,0000,0000,0000,,如果-3除以1/2呢? Dialogue: 0,0:06:51.88,0:06:52.50,Default,,0000,0000,0000,,一樣 Dialogue: 0,0:06:52.50,0:07:00.37,Default,,0000,0000,0000,,-3就等於-3/1,除以1/2 Dialogue: 0,0:07:00.37,0:07:07.94,Default,,0000,0000,0000,,就等於-3/1乘以2/1 Dialogue: 0,0:07:07.94,0:07:12.01,Default,,0000,0000,0000,,就等於 -6/1,等於-6 Dialogue: 0,0:07:12.01,0:07:15.81,Default,,0000,0000,0000,,現在,讓我給你一些理解 Dialogue: 0,0:07:17.35,0:07:19.73,Default,,0000,0000,0000,,為什麼這樣做會行得通 Dialogue: 0,0:07:19.73,0:07:24.24,Default,,0000,0000,0000,,如果說2除以1/3 Dialogue: 0,0:07:24.24,0:07:27.65,Default,,0000,0000,0000,,我們知道這就等於2/1乘以 Dialogue: 0,0:07:27.65,0:07:30.12,Default,,0000,0000,0000,,3/1,就等於6 Dialogue: 0,0:07:30.12,0:07:32.70,Default,,0000,0000,0000,,所以2、1/3、6之間有何關聯呢? Dialogue: 0,0:07:32.70,0:07:33.69,Default,,0000,0000,0000,,讓我們這樣看這件事 Dialogue: 0,0:07:33.69,0:07:36.93,Default,,0000,0000,0000,,如果我有兩片比薩 Dialogue: 0,0:07:36.93,0:07:38.66,Default,,0000,0000,0000,,我有兩片比薩 Dialogue: 0,0:07:38.66,0:07:41.52,Default,,0000,0000,0000,,這裡是我的兩片比薩 Dialogue: 0,0:07:41.52,0:07:42.53,Default,,0000,0000,0000,,2在這邊 Dialogue: 0,0:07:42.53,0:07:45.05,Default,,0000,0000,0000,,所以如果我有兩片比薩,而我想要將它們 Dialogue: 0,0:07:45.05,0:07:48.08,Default,,0000,0000,0000,,分成很多個1/3片的比薩 Dialogue: 0,0:07:48.08,0:07:50.60,Default,,0000,0000,0000,,所以我把每片比薩都分成三等份 Dialogue: 0,0:07:50.60,0:07:52.86,Default,,0000,0000,0000,,我將要畫個小賓士符號 Dialogue: 0,0:07:52.86,0:07:57.05,Default,,0000,0000,0000,,所以我把每片比薩分成三等份,對吧? Dialogue: 0,0:07:57.05,0:07:58.21,Default,,0000,0000,0000,,我有幾個1/3片的比薩呢? Dialogue: 0,0:07:58.21,0:08:02.92,Default,,0000,0000,0000,,讓我們看看,1、2、3、4、5、6 Dialogue: 0,0:08:02.92,0:08:04.80,Default,,0000,0000,0000,,我有6個1/3片的比薩 Dialogue: 0,0:08:04.80,0:08:08.14,Default,,0000,0000,0000,,所以你可能想要坐下,然後思考一下 Dialogue: 0,0:08:08.14,0:08:12.85,Default,,0000,0000,0000,,但我想這可能對你來說有些許意義 Dialogue: 0,0:08:12.85,0:08:17.19,Default,,0000,0000,0000,,讓我們再做一題讓你的腦袋累一下 Dialogue: 0,0:08:17.19,0:08:25.75,Default,,0000,0000,0000,,假設-7/2除以-4/9 Dialogue: 0,0:08:25.75,0:08:30.58,Default,,0000,0000,0000,,這就等於-7/2乘以 Dialogue: 0,0:08:30.58,0:08:33.72,Default,,0000,0000,0000,,-9/4,對吧? Dialogue: 0,0:08:33.72,0:08:37.95,Default,,0000,0000,0000,,我剛剛乘以-4/9的倒數 Dialogue: 0,0:08:37.95,0:08:41.22,Default,,0000,0000,0000,,9乘以7等於,-7乘以-9 Dialogue: 0,0:08:41.22,0:08:47.80,Default,,0000,0000,0000,,等於63,而2乘以4等於8 Dialogue: 0,0:08:47.80,0:08:51.46,Default,,0000,0000,0000,,我想你現在已經知道如何做分數的除法 Dialogue: 0,0:08:51.46,0:08:55.96,Default,,0000,0000,0000,,你可以試試 Dialogue: 0,0:08:55.96,0:08:57.31,Default,,0000,0000,0000,,分數除法的模組 Dialogue: 0,0:08:57.31,0:08:58.89,Default,,0000,0000,0000,,祝你學習愉快!