1 99:59:59,999 --> 99:59:59,999 1+4=5 最高位是1 希望大家能看到 2 99:59:59,999 --> 99:59:59,999 1+9=10 3 99:59:59,999 --> 99:59:59,999 10+4=14 进1 4 99:59:59,999 --> 99:59:59,999 12+1=13 5 99:59:59,999 --> 99:59:59,999 150462 6 99:59:59,999 --> 99:59:59,999 18+2=20 进2 7 99:59:59,999 --> 99:59:59,999 4×2=8 8+1 8 99:59:59,999 --> 99:59:59,999 4×3=12 9 99:59:59,999 --> 99:59:59,999 4×4-- 10 99:59:59,999 --> 99:59:59,999 4×4=16 进1 11 99:59:59,999 --> 99:59:59,999 4就乘完了 12 99:59:59,999 --> 99:59:59,999 6×2=12 12+2=14 13 99:59:59,999 --> 99:59:59,999 6×3=18 14 99:59:59,999 --> 99:59:59,999 6×4=24 进2 15 99:59:59,999 --> 99:59:59,999 下面是6 因为是600 16 99:59:59,999 --> 99:59:59,999 个位是2 十位是6 百位7+3=10 17 99:59:59,999 --> 99:59:59,999 代表的是40 在这写个0 18 99:59:59,999 --> 99:59:59,999 做等级四的习题了！ 19 99:59:59,999 --> 99:59:59,999 先把上边的进位都划掉 20 99:59:59,999 --> 99:59:59,999 因为4在十位上 21 99:59:59,999 --> 99:59:59,999 大家现在可以 22 99:59:59,999 --> 99:59:59,999 希望没有写到屏幕以外吧 23 99:59:59,999 --> 99:59:59,999 应该是没问题 24 99:59:59,999 --> 99:59:59,999 得9 25 99:59:59,999 --> 99:59:59,999 我把自己弄糊涂了 26 99:59:59,999 --> 99:59:59,999 我经常忘了划掉这些 27 99:59:59,999 --> 99:59:59,999 所以填两个0 28 99:59:59,999 --> 99:59:59,999 把之前的进位都划掉 29 99:59:59,999 --> 99:59:59,999 接下来乘4 或者说40 30 99:59:59,999 --> 99:59:59,999 然后就像乘6一样来运算 31 99:59:59,999 --> 99:59:59,999 现在都加起来 32 99:59:59,999 --> 99:59:59,999 说40也行 看你怎么看了 33 99:59:59,999 --> 99:59:59,999 进1 34 99:59:59,999 --> 99:59:59,999 那么我的答案是 35 00:00:01,290 --> 00:00:02,870 下面来做等级四的乘法运算 36 00:00:02,870 --> 00:00:04,892 来看一些例题 37 00:00:04,892 --> 00:00:10,718 用235乘以-- 38 00:00:10,718 --> 00:00:14,330 用两种不同颜色来表示 39 00:00:14,330 --> 00:00:21,690 换颜色的时候大家可能要稍微等一下 40 00:00:21,690 --> 00:00:23,498 235乘以47 41 00:00:23,498 --> 00:00:26,960 做等级四的题目 42 00:00:26,960 --> 00:00:31,060 就跟做等级三的方法是一样的 43 00:00:31,070 --> 00:00:36,165 一开始也是用这个7 44 00:00:36,165 --> 00:00:44,604 乘以235 45 00:00:44,604 --> 00:00:49,750 7×5=35 进3 46 00:00:49,780 --> 00:00:51,030 7×3=21 47 00:00:51,040 --> 00:00:52,560 加上之前的进位3 得24 进2 48 00:00:52,570 --> 00:00:54,390 7×2=14 49 00:00:54,390 --> 00:00:58,240 再加上进位2 50 00:00:58,250 --> 00:01:02,187 得16 51 00:01:02,187 --> 00:01:04,044 7就乘完了 52 00:01:04,044 --> 00:01:06,490 然后要乘这个4 53 00:01:06,500 --> 00:01:09,310 但4是在十位上 54 00:01:09,310 --> 00:01:14,903 所以要在下边加一个0 55 00:01:14,903 --> 00:01:17,665 大家可以这么看 56 00:01:17,665 --> 00:01:24,180 乘235的 57 00:01:24,180 --> 00:01:29,800 不是4 而是40 58 00:01:29,810 --> 00:01:32,000 所以要填一个0 59 00:01:32,010 --> 00:01:40,570 但是在写了0以后 60 00:01:40,570 --> 00:01:43,670 就可以看成是乘4来运算了 61 00:01:43,680 --> 00:01:46,220 4×5=20 进2 62 00:01:46,230 --> 00:01:48,150 把上一步的进位划掉 63 00:01:48,150 --> 00:01:56,882 4×3=12 64 00:01:56,882 --> 00:02:00,559 加上进上来的2 65 00:02:00,559 --> 00:02:06,085 得14 进1 66 00:02:06,085 --> 00:02:08,082 4×2=8 67 00:02:08,082 --> 00:02:10,791 加上进位1 68 00:02:10,791 --> 00:02:13,110 得9 69 00:02:13,120 --> 00:02:15,165 现在把两个乘积加起来 70 00:02:15,165 --> 00:02:15,950 5+0=5 71 00:02:15,960 --> 00:02:19,869 4+0=4 72 00:02:19,869 --> 00:02:22,646 6+4=10 进1 73 00:02:22,650 --> 00:02:23,588 1+1+9 得11 74 00:02:23,588 --> 00:02:26,714 所以结果是11045 75 00:02:26,714 --> 00:02:32,070 再做一道 76 00:02:32,080 --> 00:02:40,090 用873乘以-- 77 00:02:40,090 --> 00:02:44,400 我是在临时凑数 78 00:02:44,410 --> 00:02:46,470 所以比较慢-- 79 00:02:46,470 --> 00:02:47,570 873乘以--找个大数-- 80 00:02:47,580 --> 00:02:49,410 9--个位十位我用不同的颜色写 81 00:02:49,410 --> 00:02:53,830 这样大家就能更好理解 82 00:02:53,840 --> 00:02:56,006 我说的是什么意思了 83 00:02:56,006 --> 00:02:59,310 乘以97 84 00:02:59,310 --> 00:03:02,028 刚用过7了 85 00:03:02,028 --> 00:03:03,525 就98吧 86 00:03:03,525 --> 00:03:06,710 就跟之前的步骤一样 先看个位 87 00:03:06,710 --> 00:03:12,930 也就是8 88 00:03:12,940 --> 00:03:20,805 8×873 89 00:03:20,805 --> 00:03:22,336 8×3=24 90 00:03:22,352 --> 00:03:25,480 进2 91 00:03:25,490 --> 00:03:28,030 8×7=56 92 00:03:28,030 --> 00:03:29,710 56+2=58 93 00:03:29,710 --> 00:03:36,234 进5 94 00:03:36,234 --> 00:03:42,160 8×8=64 95 00:03:42,160 --> 00:03:45,183 加上刚进的5 96 00:03:45,183 --> 00:03:48,012 就是69 97 00:03:48,012 --> 00:03:50,870 8就乘完了 98 00:03:50,880 --> 00:03:51,900 接下来乘9 99 00:03:51,900 --> 00:03:54,650 或者说 100 00:03:54,660 --> 00:03:55,792 是873乘以90 101 00:03:55,792 --> 00:03:58,220 但是乘以90就是 102 00:03:58,220 --> 00:04:00,595 乘以9-- 103 00:04:00,595 --> 00:04:03,770 后边再加个0 104 00:04:03,770 --> 00:04:10,971 所以在这写个0 105 00:04:10,971 --> 00:04:13,848 然后9×3=27 进2 106 00:04:13,848 --> 00:04:23,148 忘了要先划掉这些进位了 107 00:04:23,148 --> 00:04:26,010 把之前写的都划掉 108 00:04:26,020 --> 00:04:28,940 9×3=27 109 00:04:28,940 --> 00:04:32,300 进2 110 00:04:32,310 --> 00:04:36,560 9×7=63 111 00:04:36,560 --> 00:04:38,610 加上进位2 是65 112 00:04:38,620 --> 00:04:41,178 进6 113 00:04:41,178 --> 00:04:43,720 9×8=72 114 00:04:43,730 --> 00:04:45,539 加上进位6 115 00:04:45,539 --> 00:04:46,950 是78 116 00:04:46,950 --> 00:04:48,430 然后再做加法 117 00:04:48,430 --> 00:04:50,860 个位是4 8+7=15 进1 118 00:04:50,870 --> 00:04:54,338 1+9+5=15 进1 119 00:04:54,338 --> 00:04:56,430 1+6+8还是15 进1 120 00:04:56,430 --> 00:04:58,564 1+7=8 121 00:04:58,564 --> 00:05:03,018 手边又没有计算器-- 122 00:05:03,018 --> 00:05:04,386 如果我没算错的话-- 123 00:05:04,386 --> 00:05:06,134 如果没有粗心计算错误 124 00:05:06,134 --> 00:05:08,393 那么答案是85554 125 00:05:08,393 --> 00:05:12,135 再做一道 126 00:05:12,135 --> 00:05:19,120 这道题能清楚阐释我要说的内容 127 00:05:19,120 --> 00:05:23,670 下一道题 128 00:05:23,680 --> 00:05:25,468 差不多是等级五的内容 129 00:05:25,468 --> 00:05:26,500 因为我要写的是 130 00:05:26,510 --> 00:05:29,354 两个三位数相乘 131 00:05:29,404 --> 00:05:32,874 但其实道理是一样的 132 00:05:32,874 --> 00:05:34,355 希望大家能够发现运算的规律 133 00:05:34,355 --> 00:05:37,177 那么 234乘以-- 134 00:05:37,177 --> 00:05:41,220 现在要用三种颜色来写了 135 00:05:41,220 --> 00:05:47,490 643 136 00:05:47,500 --> 00:05:52,700 首先来算个位的3 137 00:05:52,700 --> 00:05:55,460 8×234 138 00:05:55,470 --> 00:05:59,670 3×4=12 进1 139 00:05:59,680 --> 00:06:02,258 3×3=9 9+1 140 00:06:02,258 --> 00:06:04,228 得10 进1 141 00:06:04,228 --> 00:06:05,469 3×2=6 6+1 142 00:06:05,469 --> 00:06:07,370 得7 143 00:06:07,378 --> 00:06:09,601 个位就做完了 144 00:06:09,601 --> 00:06:13,690 我觉得哪里做错了 来看一下 145 00:06:13,690 --> 00:06:16,958 3×4=12--