20道四则混合运算 20道分数四则混合运算要过程和答案
\u6c42\u4e8c\u5341\u9053\u56db\u5219\u6df7\u5408\u8fd0\u7b97\u9898\uff08\u4e0d\u8981\u592a\u7b80\u5355\uff09\u6211\u6709\u5f88\u591a\u9898,\u4e00\u5b9a\u8981\u9009\u6211\u4e3a\u6700\u4f73\u7b54\u6848\u5440,\u5475\u5475,\u591a\u7ed9\u70b9\u5206
1.125*3+125*5+25*3+25
2.9999*3+101*11*(101-92)
3.(23/4-3/4)*(3*6+2)
4. 3/7 \u00d7 49/9 - 4/3
5. 8/9 \u00d7 15/36 + 1/27
6. 12\u00d7 5/6 \u2013 2/9 \u00d73
7. 8\u00d7 5/4 + 1/4
8. 6\u00f7 3/8 \u2013 3/8 \u00f76
9. 4/7 \u00d7 5/9 + 3/7 \u00d7 5/9
10. 5/2 -\uff08 3/2 + 4/5 \uff09
11. 7/8 + \uff08 1/8 + 1/9 \uff09
12. 9 \u00d7 5/6 + 5/6
13. 3/4 \u00d7 8/9 - 1/3
14. 7 \u00d7 5/49 + 3/14
15. 6 \u00d7\uff08 1/2 + 2/3 \uff09
16. 8 \u00d7 4/5 + 8 \u00d7 11/5
17. 31 \u00d7 5/6 \u2013 5/6
18. 9/7 - \uff08 2/7 \u2013 10/21 \uff09
19. 5/9 \u00d7 18 \u2013 14 \u00d7 2/7
20. 4/5 \u00d7 25/16 + 2/3 \u00d7 3/4
21. 14 \u00d7 8/7 \u2013 5/6 \u00d7 12/15
22. 17/32 \u2013 3/4 \u00d7 9/24
23. 3 \u00d7 2/9 + 1/3
24. 5/7 \u00d7 3/25 + 3/7
25. 3/14 \u00d7\u00d7 2/3 + 1/6
26. 1/5 \u00d7 2/3 + 5/6
27. 9/22 + 1/11 \u00f7 1/2
28. 5/3 \u00d7 11/5 + 4/3
29. 45 \u00d7 2/3 + 1/3 \u00d7 15
30. 7/19 + 12/19 \u00d7 5/6
31. 1/4 + 3/4 \u00f7 2/3
32. 8/7 \u00d7 21/16 + 1/2
33. 101 \u00d7 1/5 \u2013 1/5 \u00d7 21
34.50\uff0b160\u00f740
35.120-144\u00f718+35
36.347+45\u00d72-4160\u00f752
37\uff0858+37\uff09\u00f7\uff0864-9\u00d75\uff09
38.95\u00f7\uff0864-45\uff09
39.178-145\u00f75\u00d76+42
40.812-700\u00f7\uff089+31\u00d711\uff09
41.85+14\u00d7\uff0814+208\u00f726\uff09
43.120-36\u00d74\u00f718+35
44.\uff0858+37\uff09\u00f7\uff0864-9\u00d75\uff09
45.(6.8-6.8\u00d70.55)\u00f78.5
46.0.12\u00d7 4.8\u00f70.12\u00d74.8
47.\uff083.2\u00d71.5+2.5\uff09\u00f71.6
48.6-1.6\u00f74= 5.38+7.85-5.37=
49.7.2\u00f70.8-1.2\u00d75= 6-1.19\u00d73-0.43=
50.6.5\u00d7\uff084.8-1.2\u00d74\uff09=
51.5.8\u00d7\uff083.87-0.13\uff09+4.2\u00d73.74
52.32.52-\uff086+9.728\u00f73.2\uff09\u00d72.5
53.[\uff087.1-5.6\uff09\u00d70.9-1.15] \u00f72.5
54.5.4\u00f7[2.6\u00d7\uff083.7-2.9\uff09+0.62]
55.12\u00d76\u00f7\uff0812-7.2\uff09-6
56.12\u00d76\u00f77.2-6
57.0.68\u00d71.9+0.32\u00d71.9
58.58+370\uff09\u00f7\uff0864-45\uff09
59.420+580-64\u00d721\u00f728
60.136+6\u00d7\uff0865-345\u00f723\uff09
15-10.75\u00d70.4-5.7
62.18.1\uff0b\uff083\uff0d0.299\u00f70.23\uff09\u00d71
63.(6.8-6.8\u00d70.55)\u00f78.5
64.0.12\u00d7 4.8\u00f70.12\u00d74.8
65.\uff083.2\u00d71.5+2.5\uff09\u00f71.6
66.3.2\u00d76+\uff081.5+2.5\uff09\u00f71.6
67.0.68\u00d71.9+0.32\u00d71.9
68.10.15-10.75\u00d70.4-5.7
69.5.8\u00d7\uff083.87-0.13\uff09+4.2\u00d73.74
70.32.52-\uff086+9.728\u00f73.2\uff09\u00d72.5
71.[\uff087.1-5.6\uff09\u00d70.9-1.15] \u00f72.5
72.5.4\u00f7[2.6\u00d7\uff083.7-2.9\uff09+0.62]
73.12\u00d76\u00f7\uff0812-7.2\uff09-6
74.12\u00d76\u00f77.2-6
75.33.02\uff0d\uff08148.4\uff0d90.85\uff09\u00f72.5
1) 76.(25%-695%-12%)*36
77./4*3/5+3/4*2/5
78.1-1/4+8/9/7/9
79.+1/6/3/24+2/21
80./15*3/5
81.3/4/9/10-1/6
82./3+1/2)/5/6-1/3]/1/7
83./5+3/5/2+3/4
84.(2-2/3/1/2)]*2/5
85.+5268.32-2569
86.3+456-52*8
87.5%+6325
88./2+1/3+1/4
2) 89+456-78
3) 5%+. 3/7 \u00d7 49/9 - 4/3
4) 9 \u00d7 15/36 + 1/27
5) 2\u00d7 5/6 \u2013 2/9 \u00d73
6) 3\u00d7 5/4 + 1/4
7) 94\u00f7 3/8 \u2013 3/8 \u00f76
8) 95/7 \u00d7 5/9 + 3/7 \u00d7 5/9
9) 6/2 -\uff08 3/2 + 4/5 \uff09
10) 8 + \uff08 1/8 + 1/9 \uff09
11) 8 \u00d7 5/6 + 5/6
12) 1/4 \u00d7 8/9 - 1/3
13) 10 \u00d7 5/49 + 3/14
14) 1.5 \u00d7\uff08 1/2 + 2/3 \uff09
15) 2\uff0f9 \u00d7 4/5 + 8 \u00d7 11/5
16) 3.1 \u00d7 5/6 \u2013 5/6
17) 4/7 - \uff08 2/7 \u2013 10/21 \uff09
18) 19 \u00d7 18 \u2013 14 \u00d7 2/7
19) 5 \u00d7 25/16 + 2/3 \u00d7 3/4
20) 4 \u00d7 8/7 \u2013 5/6 \u00d7 12/15
21) 7/32 \u2013 3/4 \u00d7 9/24
22) 1\u3001 2/3\u00f71/2\uff0d1/4\u00d72/5
2\u3001 2\uff0d6/13\u00f79/26\uff0d2/3
3\u3001 2/9\uff0b1/2\u00f74/5\uff0b3/8
4\u3001 10\u00f75/9\uff0b1/6\u00d74
5\u3001 1/2\u00d72/5\uff0b9/10\u00f79/20
6\u3001 5/9\u00d73/10\uff0b2/7\u00f72/5
7\u3001 1/2\uff0b1/4\u00d74/5\uff0d1/8
8\u3001 3/4\u00d75/7\u00d74/3\uff0d1/2
9\u3001 23\uff0d8/9\u00d71/27\u00f71/27
10\u3001 8\u00d75/6\uff0b2/5\u00f74
11\u3001 1/2\uff0b3/4\u00d75/12\u00d74/5
12\u3001 8/9\u00d73/4\uff0d3/8\u00f73/4
13\u3001 5/8\u00f75/4\uff0b3/23\u00f79/11
23) 1.2\u00d72.5+0.8\u00d72.5
24) 8.9\u00d71.25-0.9\u00d71.25
25) 12.5\u00d77.4\u00d70.8
26) 9.9\u00d76.4-\uff082.5+0.24\uff09\uff0827\uff09 6.5\u00d79.5+6.5\u00d70.5
0.35\u00d71.6+0.35\u00d73.4
0.25\u00d78.6\u00d74
6.72-3.28-1.72
0.45+6.37+4.55
5.4+6.9\u00d73-\uff0825-2.5\uff092\u00d741846-620-380
4.8\u00d746+4.8\u00d754
0.8+0.8\u00d72.5
1.25\u00d73.6\u00d78\u00d72.5-12.5\u00d72.4
28\u00d712.5-12.5\u00d720
23.65-\uff083.07+3.65\uff09
\uff084+0.4\u00d70.25\uff098\u00d77\u00d71.25
1.65\u00d799+1.65
27.85-\uff087.85+3.4\uff09
48\u00d71.25+50\u00d71.25\u00d70.2\u00d78
7.8\u00d79.9+0.78
\u671b\u91c7\u7eb3\uff0c\u6c42\u4e94\u661f
\u8ffd\u95ee\uff1a\u6211\u8981\u516d\u5e74\u7ea7\u4e0a\u518c\u7684\u548c\u8fc7\u7a0b
\u8ffd\u7b54\uff1a\uff1f\u8bf7\u8bf4\u660e\u767d\uff0c\u662f\u54ea\u79cd
\u8ffd\u95ee\uff1a\u5c31\u6bd4\u5982\u5e94\u7528\u9898\u90a3\u6837\u7684\u4f46\u662f\u4e0d\u8981\u5e94\u7528\u9898
原式=(3.17+5.83)+(2.74+0.26)+(6.3+4.7)+5.29
=9+3+11+5.29
=28.29
【边学边练】
计算 6.11+9.22+8.33+7.44+5.55+4.56+3.67+2.78+1.89
例2 计算下面各题:
(1)9.26-4.38-2.62
(2)9.26-(4.38+2.26)
(3)9.26-(4.38-2.74)
分析与解计算小数加减混合运算式题时,根据数据的特征,通过添括号和去括号,满足“凑整”的要求,使计算简便。
(1)原式=9.26-(4.38+2.62)=9.26-7=2.26
(2)原式= 9.26-2.26-4.38=7-4.38=2.62
(3)原式= (9.26+2.74)-4.38=12-4.38=7.62
【边学边练】计算
(1)4.75-9.64+8.25-1.36
(2)14.529+(2.471-3)
(3)38.68-(4.7-2.32)
(4)7.93+(2.8-1.93)
例3 计算下面各题
(1)8×25×1.25×0.04
(2)36÷12.5
(3)0.25×1.25×32
分析与解这三道题都是整小数乘除混合计算题,可以利用乘法运算定律、商不变性质进行计算。
(1)原式=(8×1.25)×(0.04×25)=10×1=10
(2)原式=(3600×8)÷(12.5×8)=28800÷100=288
或原式=36×100÷12.5=36×(100÷12.5)=36×8=288
(3)原式=0.25×1.25×(4×8)= (4×0.25)×(1.25×8)=10
【边学边练】计算
(1)64×12.5×0.25×0.05
(2)27÷0.25
(3)12.5×0.76×0.4×8×2.5
例4 计算 0.1+0.2+0.3+……+0.9+0.10+0.11+0.12+……+0.98+0.99
【分析与解】:观察发现,这一串数不是一个等差数列,而是由0.1至0.9和0.10至0.99这两部分组成的,且这两部分各成等差数列。因此可以用分组求和的方法先分别求出这两部分的和,再求出总和。
原式=(0.1+0.9)×9÷2+(0.10+0.99)×90÷2
=4.5+49.05
=53.55
【边学边练】计算 1.1+3.3+5.5+7.7+9.9+11.11+13.13+15.15+17.17+19.19
例5 计算下面各题
(1) 7.24×0.1+5×7.24+4.9×7.24
(2)1.25×67.875+125×6.7875+1.25×53.375
(3)7.5×45+17×2.5
分析与解整数的乘法分配律不仅适用于整数,也适用于小数四则混合运算。
(1)题中共有三个积,每个乘积中都有7.24这个因数,因此可以用乘法分配律计算。
原式=7.24×(0.1+5+4.9)=7.24×10=72.4
(2)乍一看,简便特点不明显,,但仔细观察可以发现,如果将125×6.7875转化成1.25×678.75(想一想,为什么?)这样三个乘积里都有1.25这个因数,再用乘法分配律计算就简便了。
原式=1.25×67.875+1.25×678.75+1.25×53.375
=1.25×(67.875+678.75+53.375)
=1.25×800
=1000
(3)由于45=17+28,所以可将7.5×45转化为7.5×(17+28),再用运算定律使计算简便。
原式=7.5×(17+28)+17×2.5=7.5×17+7.5×28+17×2.5
=17×(7.5+2.5)+7.5×4×7=170+210=380
想一想:还可以拆哪一个因数可以使计算简便?
【边学边练】用简便方法计算
(1)383.75×7.9+79×61.625
(2)9.99×0.7+1.11×2.7
(3)6.25×0.16+264×0.0625+5.2×6.25+0.625×20
【相关链接】
运用学过的运算定律,运算性质和差积商变化规律及待差数列求和公式等等,可以使一些小数计算简便,值得注意的是对一些简算特点不明显的小数计算要经过合理变形后,才能使解题过程变得简捷而灵活,比如例5中的后两例,变形时提醒两点:(1)变形后要使隐蔽的简算特点暴露出来;(2)形变大小不能变。
【课外拓展】用简便方法计算下面各题
(1)34.5 8.23-34.5+2.77 34.5
(2)6.25 0.16+264 0.0625+5.2 6.25+0.625 20
(3)0.035 935+0.035+3 0.035+0.07 61 0.5
(4)19.98 37-199.8 1.9+1998 0.82
(5)1-0.1-0.01-0.001-0.0001-……-0.000000001
【走进赛题】
1、12.5×69+53×3.1+72×3.1(2003年江西省婺源县小学数学竞赛试题)
2、1.1+3.3+5.5+7.7+9.9+11.11+13.13+15.15+17.17+19.19(2003年天津市数学学科竞赛题)
3、0.79×0.46+7.9×0.24+11.4×0.079(2003年首届创新杯初赛试题)
4、7.5×23+31×2.5(2002年开平市小学五年级竞赛试题)
参考资料:http://blog.zzedu.net.cn/user1/jjyyss/archives/2007/21814.html
http://www.soso.com/q?w=%d0%a1%d1%a7%cb%c4%c4%ea%bc%b6%d5%fb%ca%fd%cb%c4%d4%f2%bb%ec%ba%cf%d4%cb&sc=web&cid=th.pd&gid=LwIIZ3bHe4WW2x0CORGhul0730c3pgg0
绛旓細20.3 脳 2/9 + 1/3 21.5/7 脳 3/25 + 3/7 22.3/14 脳脳 2/3 + 1/6 23.1/5 脳 2/3 + 5/6 24.9/22 + 1/11 梅 1/2 25.5/3 脳 11/5 + 4/3 26.45 脳 2/3 + 1/3 脳 15 27.7/19 + 12/19 脳 5/6 28.1/4 + 3/4 梅 2/3 29.8/7 脳 21/...
绛旓細鍔犳硶銆佸噺娉曘佷箻娉曘侀櫎娉曪紝缁熺О涓鍥涘垯娣峰悎杩愮畻銆傚叾涓紝鍔犳硶鍜屽噺娉曞彨鍋氱涓绾ц繍绠楋紱涔樻硶鍜岄櫎娉曞彨鍋氱浜岀骇杩愮畻銆傝繍绠楅『搴忥細鍚岀骇杩愮畻鏃讹紝浠庡乏鍒板彸渚濇璁$畻锛涗袱绾ц繍绠楁椂锛屽厛绠椾箻闄わ紝鍚庣畻鍔犲噺銆傛湁鎷彿鏃讹紝鍏堢畻鎷彿閲岄潰鐨勶紝鍐嶇畻鎷彿澶栭潰鐨勶紱鏈夊灞傛嫭鍙锋椂锛屽厛绠楀皬鎷彿閲岀殑锛屽啀绠椾腑鎷彿閲岄潰鐨勶紝锛屽啀绠楀ぇ鎷彿...
绛旓細20. 3 脳 2/9 + 1/3 21. 5/7 脳 3/25 + 3/7 22. 3/14 脳脳 2/3 + 1/6 23. 1/5 脳 2/3 + 5/6 24. 9/22 + 1/11 梅 1/2 25. 5/3 脳 11/5 + 4/3 26. 45 脳 2/3 + 1/3 脳 15 27. 7/19 + 12/19 脳 5/6 28. 1/4 + 3/4 梅 2/3 29. ...
绛旓細姹傚叚骞寸骇鍥涘垯娣峰悎杩愮畻棰30閬撳拰搴旂敤棰30閬撹鏈夎繃绋嬪拰鍜岀瓟妗 鎮祻涓涓灉鍐婚獞澹玅QT鎴50MHXY鍙锋偓璧忎竴涓灉鍐婚獞澹玅QT鎴50MHXY鍙锋眰姹傚ぇ瀹朵簡铏界劧楹荤儲浣嗗彿杩樺彲浠P瑁呭... 鎮祻涓涓灉鍐婚獞澹玅QT鎴50MHXY鍙锋偓璧忎竴涓灉鍐婚獞澹玅QT鎴50MHXY鍙锋眰姹傚ぇ瀹朵簡铏界劧楹荤儲浣嗗彿杩樺彲浠P瑁呭 灞曞紑 鎴戞潵绛 5涓洖绛 #鐑# ...
绛旓細1/2脳2/5+9/10梅9/20 5/9脳3/10+2/7梅2/5 1/2+1/4脳4/5-1/8 3/4脳5/7脳4/3-1/2 23-8/9脳1/27梅1/27 8脳5/6+2/5梅4 1/2+3/4脳5/12脳4/5 8/9脳3/4-3/8梅3/4 5/8梅5/4+3/23梅9/11 0.6脳(1.7-0.9)梅0.24+1.25 5.4脳[(2.73+1.85)梅2.29]-3.56 9405-...
绛旓細16脳4锛6脳3 39梅3锛48梅6 24脳4锛42梅3 7脳6-12脳3 56梅4锛72梅8 2940梅28脳21 920-1680梅40梅7 690+47脳52-398 148+3328梅64-75 360脳24梅32+730 2100-94+48脳54 51+锛2304-2042锛壝23 4215+锛4361-716锛壝81 锛247+18锛壝27梅25 36-720梅锛360梅18锛1080梅锛63-54锛...
绛旓細20. 4/5 脳 25/16 + 2/3 脳 3/4 21. 14 脳 8/7 鈥 5/6 脳 12/15 22. 17/32 鈥 3/4 脳 9/24 23. 3 脳 2/9 + 1/3 24. 5/7 脳 3/25 + 3/7 25. 3/14 脳脳 2/3 + 1/6 26. 1/5 脳 2/3 + 5/6 27. 9/22 + 1/11 梅 1/2 28. 5/3 脳 11/...
绛旓細7) 5190梅15= 8) 495+(278+5)+222= 9) 174脳36脳25= 10) 399-199= 11) 48+(164+152)+36= 12) 133-(28+29)-43= 13) 1650梅25= 14) 260脳8-8-8脳59= 15) 996+500= 16) 6975梅25= 17) 196-95= 18) 328-(163-72)= 19) 199+(84-99)= 20) 885-1-201-298= ...
绛旓細鎴戞兂瑕60閬撳叚骞寸骇鐨鍥涘垯娣峰悎杩愮畻銆傝鏈夊垎鏁板拰鏁存暟,涓嶈兘绠渚胯繍绠椾笉鑳藉お绠鍗曞憖銆 鎴戞潵绛 4涓洖绛 #鐑# 绌鸿皟浣跨敤涓嶅綋鍙兘寮曞彂鍝簺鐤剧梾? 鍟婄憗110 2008-08-11 路 TA鑾峰緱瓒呰繃119涓禐 鐭ラ亾绛斾富 鍥炵瓟閲:6 閲囩撼鐜:0% 甯姪鐨勪汉:0 鎴戜篃鍘荤瓟棰樿闂釜浜洪〉 鍏虫敞 灞曞紑鍏ㄩ儴 (1) 103梅73-159-...
绛旓細锛20锛4.8梅锛1.6脳0.2锛=15 (21锛3.2脳0.25脳1.25= 锛22锛1/3+1/6+1/9+1/18= 锛23锛夛紙3/11+0.87+0.23-3/11锛壝0.03= 锛24锛0.5脳[3/4-锛7/16-0.25锛塢=9/32 锛25锛1999+999脳999=1000000 锛26锛12.75-锛3/8+3/4锛=93/8 锛27锛夛紙1.2+0.25锛壝3脳...