简便运算的练习题和答案

1、创作编号:BG7531400019813488897SX创别如克,运算定律练习题(1)乘法交换律：aXb=bXa乘法结合律：(aXb)Xc=aX(bXc)38X25X442X125X825X17X4(25X125)X(8X4)(2)乘法交换律和结合律的变化练习125X64125X8844X2525X28(3)加法交换律：a+b=b+a加法结合律：(a+b)+c=a+(b+c)357+288+143158+395+105167+289+33129+235+171+165378+527+73169+78+2258+39+42+61138+293+62+107(4)乘法分配律：(a+b)Xc=aXc

2、+bXc正用练习49X4X538X125X8X3(125X25)X45X289X2(125X12)X8125X(12X4)125X2458X101-58创作编号:BG7531400019813488897SX创别如克*【思路导航】在除法里,被除数和除数同时乘或除以一个相同的数,商不变.325 25(80+4)X2515X(20+3)(20+4)X25(125+17)X825X(40+4)5乘法分配律正用的变化练习：36x325x4139x101201X24125x88(6)乘法分配律反用的练习：34X72+34X2835X37+65X3785X82+85X1825X97+25X376X25+2

3、5X24(7)乘法分配律反用的变化练习：38X29+3875X2994-7564X199+6435X68+68+68X64思考题：8其他的一些简便运算.800 256000+1253600+8+574X99=(325x4)v(25x4)=1300+100=13【练一练1】(1)450 253500X25【经典例题二】计算25x125x4x8【思路导航】如果先把25与4相乘,可以得到100,同时把125与8相乘,可以得到1000;再把100和1000相乘就可以了.运用了乘法交换律和结合律.25x125x4x8=(25x4)x125x8)=100 x1000=100000【练一练2(1)125x1

4、5x8x4(2)25x24(3)125x16【经典例题三】计算：(1)125x34+125x66(2)43x11+43x36+43x52+43【思路导航】利用乘法分配律来计算这两题(1)125x34+125x66(2)43x11+43x36+43x52+43=125x(34+66)=43x(11+36+52+1)=125x100=43x10021x73+26x21+21【经典例题四】计算(D(360+108)-36(2)525+25(3)(4)10000 6259000+225(5)495004-900(6)(4)75x1625x5x64x125(5)125x25x32=12500【练一练3】

5、计算下面各题:(1)125x64+125x36=4300(2)64x45+64x71-64x16(2)Iv2+3v2+5v2+7v2【思路导航】两个数的和、差除以一个数,可以用这个数分别去除这两个数,再求出两个商的和(差利用这一性质,可以使计算简便.(1)(360+108)+36(2)1+2+3+2+5+2+7+2=360+36+108+36=(1+3+5+7)+2=10+3=16+2=13=8【练一练4】(1)(720+96)+24(2)(4500-90)+45(3)6342+21(5)73+36+105+36+146+36(6)(10000-1000-100-10)+10【经典例题五】15

6、8x61+79x3【思路导航】在乘除混合运算中,如果算式中没有括号,计算式可以根据运算定律和性质调换乘数或者除数的位置,只要计算：数字跟着前面的符号一起移动.158x61+79x3=1584-79x61x3=2x61x3=366【练一练5】计算下面各题：(1)238x36+119x5(2)138x2769x50【经典例题六】计算下面各题：(1)103x96+16(2)200+(25X)【思路导航】这两道题都是乘除法混合运算,我们可以根据这两道题的特点,采用加括号和去括号的方法,使计算简便.可以概括为：括号前是乘号,加、去括号不改号,括号前是除号,田、去括号要改号.(1)103x964-16(2

7、)200+(25+4)=103x(96X6)=200+25x4=103x6=8x4=618【练一练6】计算下面各题:(1)612x3664-183(4)8811+89(3)624x48+312+8(4)406x312X04+203=32(2)1000+(125+4)(4)241x345-r678v345x(678+241)【经典例题七】计算：(D68x62(2)85x85【思路导航】这两题的形式叫做“头同尾合十它们的计算方法是：先用两个因数的个位数相乘,并把积直接写在末尾,如果积不满10,十位上要补写0,然后再将两个因数的十位数乘它本身加1的和,积写在两个个位数积的前面.(1)68x62第一步

8、8x2=16,第二步6x(6+1)=42,合起来是4216(2)85x85第一步5x5=25,第二步是8x(8+1)=72,合起来是7225【练一练7】(1)23x27(2)46x44(3)55x55(4)91x99【经典例题八】计算：26x11【思路导航】一个两位数乘11的方法是：用两位数的头作积的头,用两位数的尾作积的尾,用这个两位数的两个数字之和作积的中间数(如果相加满十,那么把和的十位数“小加到头上.26x11第一步2作积的头,第二步6作积的尾,第三步2+6=8作中间,合起来是286o【练一练8计算(1)53x11(2)39x11(3)65x11(4)98x11【经典例题九】计算：35

9、8x11【思路导航】 三位数乘U,用三位数的头作积的头,用三位数的尾作积的尾,用三位数前两位数字组成的数加厚两位数字组成的数的和作积的中间数.358x11,第一步用3作积的头,第二步用8作积的尾,在用35+58=93,合起来是3938.【练一练9】计算(1)353x11(2)654x11(3)896x11(3)(13x8x5x6)-r(4x5x6)(4)75x16(5)125x25x32(6)25x5x64x125【练一练3】计算下面各题:(1)125x64+125x3621x73+26x21+21(2)64x45+64x71-64x16(3)【练一练4141(1)(720+96)6342+2

10、1 24(2)(4500-90)X5(3)(4)8811+89(10000-1000-100-10)+10(5)73+36+105+36+146+36(6)【练一练5】计算下面各题:创作编号:BG7531400019813488897SX创别如克*(4)100004-625(5)49500+900(6)9000+225【练一练2】(1)125x15x8x4(2)25x24【练一练1】(1)450+25(2)525+25(3)3500X25(3)125x16简便计算专题练习(181+2564)+2719378+44+114+242+222276+228+353+219(3)624x48+312+

11、8(4)406x312X04+203【练一练6】计算下面各题:(1)612x366X83(2)1000-r(125+4)(3)(13x8x5x6)v(4x5x6)(4)241x345-r678v345x(678+241)【练一练7(1)23x27(2)46x4491x99(3)55x55(4)【练一练8】计算(1)53x11(2)39x1198x11(3)65x11(4)【练一练9】计算(1)353x11(2)654x11(3)896x11158+262+138375+219+381+2255001-247-1021-232(375+1034)+(966+125)99+999+9999+999

12、99(2130+783+270)+10177755-(2187+755)10652214+638+2863065-738-899+344-2142357-183-317-3572365-1086创作编号:BG7531400019813488897sx创别如克*497-2991883-398138x25x42370+199512x253999+49875x24(13x125)x(3x8)(12+24+80)x50178x101-17883x102-83x2123x3+85x12350 x(34x4)x379x42+79+79x5716800-12021500-12549700.7004800+2

13、584x36+64x8498x19925x(24+16)7300-25430100-？210012484-24704x25简便计算练习题225x32x12532x(25+125)88x125102x7658x9875x99+2x75123x18-178x99+1788100:4+7532000-4003150+15简便计算练习题32356-(1356-721)1235-(1780-1665)75x27+19x2531x870+13x3104x(25x65+25x28)(300+6)x12(13+24)x825x(4+8)125x(35+8)84x101504x2578x10225x20499x

14、64999x9999x16638x9999X13+1378X4+78X3+78X325+199X2532X16+14X32125X32X825X32X12588X12572X1253600+25+41250+25+5简便计算练习题48100M3753000E25出1200-624-76847-527-2732100-728-772273-73-27278+463+22+37425+14+186732+580+2681034+780320+102214-(86+14)(155+230)787-(87-29)365-(65+118)455.576-285+85825-657+57690-177+7

15、7755-287+87创作编号:BG7531400019813488897SX创别如克/871-299157-99363-199968-599178X101-17883X102-83X217X23-23X735X127-35X16-11X35简便计算练习题5容易出错类型共五种类型600-60-15736-35X2020X4+20X425X405X417575:2580-20X2+6036-36-6-6100+45-100+45100+1-100+11000+8-1000+825X845X836X9:36X925X8.15X97+348X99+15+95X28102+1-102+125+75-2

16、5+7540+360-20-1013+24X8100-36+6498-18X5+25456X8:56X812X612X6280 80;26X39+61X26简便计算练习题6356X9-56X999X55+5525X8)65+35X13672-36+64324-68+3278X101-7845X13452X76+47X76+76134X56-134+48X52X2-4X4825X23X(40+4)999X999+1999184+98301695+202864-199738-380+476+120(569+468)+(432+131)704X25256-147-53373-129+29189-(8

17、9+74)28X4X25125X32X259X72X125720+16+5简便计算练习题7630 42456-(256-36)102X3598X42158+262+138375+219+381+225276+228+353+219(2130+783+270)+1017(375+1034)+(966+125)99+999+9999+999997755(2187+755)2214+638+286创作编号:BG7531400019813488897SX创别如克/简便计算练习题85001-247-1021-232(181+2564)+2719378+44+114+242+2223999+4981883

18、-39812X2575X24138X25X4(13X125)X(3X8)(12+24+80)X503065-738-1065-357899+3442357-183-3172365-1086-214497-2992370+199525X32X125102X76178X101-17875X99+2X7584X36+64X8498X19950X(34X4)X3123X18-123X3+85X12325X(24+16)178X99+17879X42+79+79X577300+25+48100+4+75158+262+1381248+24375+219+381+225简便计算练习题931504-1548

19、00 25215004-1255001-247-1021-232(181+2564)+2719378+44+114+242+222276+228+353+219(375+1034)+(966+125)(2130+783+270)+101799+999+9999+999997755-(2187+755)简便计算练习题1012X2575X24138X25X4(13X125)X(3X8)32X(25+125)2214+638+2863065-738-1065899+3442357-183-317-3572365-1086-214497-2992370+19953983999+4981883-(12+

20、24+80)X50704X2525X32X12588X125-178102X7658X98178X10184X36+64X8475X99+2X7583X102-83X298X199创作编号:BG7531400019813488897SX创别如克*(aXb)Xc=aX(bXc)12.5123X18-123X3+85X12350X(34X4)X325X(24+16)178X99+17879X42+79+79X57215004-1257300+25+48100+4+75简便计算练习题11(a+b)+c=a+(b+c)168004-1202.73+0.89+1.274.37+0.28+1.63+5.7

21、2a-bc=a(b+c)10一0.432一2.5689.35.262.7414.9-(5.2+4.9)18.32-5.47-4.3225X6.8X0.040.25X32X0.1256.4X1.25XcX(a+b)=cXa+cXb0.45X2010.58X10.150.2X994.7X9.9简便计算练习题123.28X5.7+6.72X5.72.1X99+2.1(bXc)930+0.6+563.4+2.5+0.4(7.7+1.54)4-0.7简便计算练习题1315.89+(6.75-5.89)7.85+2.34-0.85+4.6635.61.8-15.67.213.75-(3.75+6.48)4

22、7.8-7.45+2.5523X0.1+2.3X9.90.18+4.26-0.18+4.260.58XI.34-0.58XI.37 3+4+2.7X0.253.75X0.52.75 25.26X0.125+2.74+86.3+1.89.54-(1.9X8)12.8-r(0.4XL6)6.9+4.8+3.166.86-8.66-1.340.25X16.2X40.25X32X0.1257755-(2187+755)10652214+638+28630657384.2X9956.5X9.9+56.51.09X10.8一0.8X7.093.83X4.56+3.83X5.443.65X4.736.5X0

23、.375.4X11-5.413.7X0.25-3.74-410.7X16.1-1.1X10.7+10.7X5(181+2564)+2719378+44+114+242+222276+228+353+219(375+1034)+(966+125)(2130+783+270)+101799+999+9999+999992.5X(4+0.4)(1.25-0.125)X84.8X100.1158+262+138232简便计算专题练习375+219+381+2255001-247-1021-899+3442142357-183-317-3572365-1086-497-2992370+19953999+

24、4981883-39812x2575x24简便计算练习题2138x25x4(13x125)x(3x8)(12+24+80)x50704x2525x32x12532x(25+125)88x125102x7658x98178x101-17884x36+64x8475x99+2x75创作编号:BG7531400019813488897SX创别如克*50 x(34x4)x325x(24+16)178x99+17816800-120301004.21003200040021500:125简便计算练习题32356-(1356-721)1235-(1780-1665)579x42+79+79x5773004

25、.254810034:7549700.r7001248:243150+154800:2583x102-83x298x199123x18-123x3+85x12375x27+19x2(300+6)x12(13+24)x825x(4+8)125x(35+8)84x101504x2578x10225x20499x64999x9999x16638x9999X13+1378X4+78X3+78X325+199X2532X16+14X32125X32X825X32X12588X12572X1253600325:41250:25+5简便计算练习题48100M37530003125y1200-624-7621

26、00-728-772273-73-27847-527-27335X127-35X16-11X35简便计算练习题5容易出错类型共五种类型278+463+22+37425+14+186732+580+2681034+780320+102214-(86+14)787-(87-29)365-(65+118)455-(155+230)576-285+85755-287+87825-657+57690-177+77871-299968-599157-99363-199178X101-17883X102-83X217X23-23X7600-604-15736-35X2020X4+20X425X44.25X4

27、98-18X5+2556X8:56X8280-80-r12X64-12X617575+2580-20X2+6025X8:25X836X9:36X936 36:6 6100+45-100+4525X8.15X97+325X8100+1-100+148X99+11000+8-1000+85+95X28102+1-102+165+35X1325+75-25+7540+36020-1013+24X8100-36+64672-36+64324-68+3226X39+61X26简便计算练习题6356X9-56X999X55+5578X101-7852X76+47X76+76134X56-134+45X13

28、448X52X2-4X48199925X23X(40+4)999X999+184+98301695+202864-199738-创作编号:BG7531400019813488897SX创别如克*380+476+120256-147-53(569+468)+(432+131)704X2528X4X25720+16+5102X3598X42373-129+29125X32X25简便计算练习题76304-42158+262+1385001-247-1021-232378+44+114+242+222276+228+353+219189-(89+74)9X72X125456-(256-36)375+2

29、19+381+225(181+2564)+2719(375+1034)+(966+125)(2130+783+270)+101799+999+9999+999992214+638+2867755-(2187+755)3065-738-1065317-357899+3442357-183-2365-1086-214497-2992370+19953999+498简便计算练习题81883-39812X2575X24138X25X4(13X125)X(3X8)(12+24+80)X5025X32X12532X(25+125)88X125102X76178X101-17884X36+64X8475X9

30、9+2X7598X199123X18-123X3+85X12350X(34X4)X325X(24+16)178X99+17879X42+79+79X577300+25+481004-44-75158+262+138+2719378+44+114+242+222(375+1034)+(966+125)简便计算练习题1012X2575X24(13X125)X(3X8)12484-24简便计算练习题93150+154800+25215004-125375+219+381+2255001-247-1021-232(181+2564)276+228+353+219(2130+783+270)+10179

31、9+999+9999+999997755-(2187+755)2214+638+2863065-738-1065899+3442357-183-317-3572365-1086-214497-2992370+19953999+4981883-398138X25X4123X18-123X3+85X123(24+16)(12+24+80)X5032X(25+125)704X2525X32X12588X125102X7658X98178X101-17884X36+64X8498X19975X99+2X7583X102-83X2178X99+17879X42+79+79X5721500+1257300

32、+25+4(a+b)+c=a8100+4+75简 便 计 算 练 习 题11+(b+c)16800 1202.73+0.89+1.274.37+0.28+1.63+5.72创作编号:BG7531400019813488897SX创别如克50X(34X4)X325Xa-bc=a(b+c)10-0.432-2.5689.3-5.26-2.74(aXb)Xc=aX25X6.8X804(bXc)0.25X32X0.1256. 4XL25X12.50.58XI.34-0.58XI.37.3+4+2.7X0.253.75X0.52.75+25.26X0.125+2.74+8a+b+c=(bXc)14.9-

33、(5.2+4.9)18.32-5.47-4.32cX(a+b)=cXa+cXb0.45X2010.58X10.150.2X994.7X9.9简便计算练习题123.28X5.7+6.72X5.72.1X99+2.123X0.1+2.3X9.90.18+4.26一0.18+4.2695+(L9X8)12.84-(0.4X1.6)35.6-1.8-15.6-7.27. 45+2.5566.86-8.66-1.340.25X16.2X42.5X(4+0.4)(1.25-0.125)X83.83X4.56+3.83X5.445.4X11-5.43.65X4.736.5X0.3710.7X16.1-1.1

34、X10.7+10.7X5930+86+50.76.9+4.8+3.14.6663.4+2.5+0.4简便计算练习题1315.89+(6.75-5.89)(7.7+1.54)+7.85+2.34-0.85+4.2X9956.5X9.9+56.57.09X10.8-0.8X7.09第一类：加65+73+135357+288+143272+68+2813.75-75+6.48)47.8-0.25X32X0.1254.8X100.113.7X0.25-3.74-46+7+8+102+103+1049998+3+99+998+3+9第二类：减400-256-44284-159-41545-167-145

35、478-47-178344-(144+37)236 (177+36)88x12572x12542x125x8x5第四类：乘(12+50)x4018x12525x4x88x125125x(40-4)第五类：乘129+235+171+16517+145+23+35999+99+9+3第三类：乘45x4x58x(125x13)23x5x225x9x4(250 x125)x(4x8)25x4442x2599x999x78517-53-47258-42-16125x64x2576x10399x32+3246+46x59(42+25)X125+(18+15)x125167x2+167x3+167x539x

36、8+6x39-39x423x2x4+25x4x2+27x1x8+25x8x199x22+33x34第六类：除360+4+9800+5+8250+5+2600+12+5创作编号:BG7531400019813488897SX创别如克*480+5X8420 352400+257800X25240+5+12第七类：加减92+99127-98197+102354-108323+189-123248-86+48672-36+6438x46+64x3828x225-2x225-6x225(2+4+6+98+100)-(1+3+5+97+99)2005x20062006-2006x20052005158+2

37、62+138375+219+381+2255001-247-1021-232(181+2564)+2719378+44+114+242+222276+228+353+219(6467-832)+(1832-1467)1530+(592-530)-192第八类：乘除960 x46X899000X21x113702x38+1234640-r(16+4)1000+(125+4)第九类：加减乘除(98+147)v49(230-23)+23(250-25)+251736+28+1064+28125x(860+2404-12)700+612X2x4(37+15)X85+1360(375+1034)+(96

38、6+125)(2130+783+270)+101799+999+9999+999997755-(2187+755)2214+638+2863065-738-1065899+3442357-183-317-3572365-1086-2144972992370+19953999+4981883-39812x2575x24138x25x4(13x125)x(3x8)(12+24+80)x50简便计算练习题2704x2588x12525x32x12532x(25+125)102x7658x98178x101-17884x36+64x8475x99+2x75123x3+85x12383x102-83x2

39、98x199123x18一简便计算练习题32356(1356-721)531x870+13x310(300+6)x1225x(4+8)4x(25x65+25x28)125x(35+8)(13+24)x884x101504x2578x10225x20499x6499x16638x99999x99299X13+1325+199X2532X16+14X350 x(34x4)x379x42+79+79x5725x(24+16)178x99+1787300+25X0100+21008100*7516800+12032000+400215004-12549700+7001248+243150r548009

40、251235(1780-1665)75x27+19x2871-299157-99363.199968-599简便计算练习题5600-604-1520X4+20X4736-35X2025X4+25X478X4+78X3+78X3125简便计算练习题43600+25X125X32X88100+4+751200-624-762100-728-77273278+463+22+37732+580+268+18625X32X12588X12572X3000+125+81250+25+5273-73-27847-527-21034+780320+102425+14214-(86+14)787-(87-29)

41、365.(65+118)455-(155+230)576-285+85825-657+57690-177+77755-287+87175.75253636+6612X6X2X625X8+25X880-20X2+6025X8+(25X8)100+45-100+45100+1-100+18102+1-102+11048X99+165+35X131000+8-1000+825+75-25+7513+24X8+64672-36+64324-68+32简便计算练习题626x39+61x2678356x956x999x55+5552x76+47x76+76-4x48134x56-134+45x13436X

42、9+36X915X97+35+95X240+360+20,100-3678x101-48x52x2创作编号:BG7531400019813488897SX创别如克,25x23x(40+4)999x999+1999864-199738-301380+476+120(569+468)+(432+131)704x25256-147-53373-129+29简便计算练习题7720+16+5630X2456一(256-36)102x3598x42158+262+138375+219+381+2255001-2471021-232(181+2564)+2719378+44+114+242+222276+2

43、28+353+219(375+1034)+(966+125)184+98695+202189-(89+74)28x4x25125x32x259x72x125(2130+783+270)+1017(2187+755)2214+638+28699+999+9999+99999775532x(25+125)88x125102x76178x101-17884x36+64x8475x99+2x7598x199123x18-123x3+85x12350 x(34x4)x3简便计算练习题91248+2431509154800+2521500+125375+219+381+2255001-247-1021-2

44、32(181+2564)+27193065-738-1065899+3442357-183-317-3572365-1086-2144972992370+1995简便计算练习题83999+4981883-39812x2575x24138x25x45(13x125)x(3x8)(12+24+80)x5025x32x1225x(24+16)178x99+17879x42+79+79x577300+25+48100XK5158+262+138378+44+114+242+222966+125)276+228+353+219(375+1034)+(2130+783+270)+1017(2187+755

45、)99+999+9999+999997755-2214+638+2863065-738-1065899+3442357-183-317-3572365-1086-2144972992370+19953999+4981883-39812x2575x24138x25x4(13x125)x(3x8)(12+24+80)x5025+125)704x2525x32x12532x(88x1258x101-178102x7658x981784x36+64x8475x99+2x7583x298x199(a+b)+c=a+(b+c)2.73+0.89+1.274.37+0.28+L63+5.72abc=a(b+

46、c)10-0.432-2.5689.35.26-2.74(axb)xc=ax(bxc)25x6.8x0.040.25x32x0.12550.2x994.7x9.92.1x99+2.123x0.1+123x18-123x3+85x123(24+16)50 x(34x4)x325x178x99+17879x42+79+79x5721500X257300+25+48100*7516800X2014.9-(5.24-4.9)18.32-5.47-4.3283x102-cx(a+b)=cxa+cxb0.45x2010.58x10.13.28x5.7+6.72x5.76.4xL25x12.52.3x9.9

47、+2.7x0.25a-rb4-c=av(bxc)63v1.89.5T(L9x8)12.8+(0.4x1.6)930-r0.6v563.4+2.5+0.4(7.7+1.54)+0.70.18+4.26-0.18+4.260.58xL3v0.58xl.33.75x0.5-2.75-r25.26x0.125+2.74-r86.9+4.8+3.1+4.6615.89+(6.75-5.89)7.85+2.34-0.8535.61.815.67.27.45+2.5513.75-(3.75+6.48)47.8-66.868.66L342.5x(4+0.4)0.25x16.2x4(1.25-0.125)x80

48、.25x32xO.1254.8x100.14.2x9956.5x9.9+56.57.09x10.80.8x7.0910.7X16.1.L1X10.7+10.7x5倍数问题11:53:14L甲水池有水2600立方米,乙水池有水1200立方米.如果甲水池里的水以每分钟23立方米的速度流入乙水池,那么多少分钟后,乙水池里的水是甲水池的4倍？2.甲水池有42吨水,乙水池有22吨水.现同时从两个水池中向外排水,排水速度是每分钟2吨,多少分钟后,甲水池的水是乙水池的6倍？3.两个数的和是16L7,把较大数的小数点向左移动一位后就和较小数相等,这两个数各是多少？创作编号:BG7531400019813488

49、897SX创别如克*4.兄弟俩的年龄相差5岁,兄3年后的年龄是弟4年前的3倍,兄弟两人今年各多少岁？5.某工程甲队独做50天可以完成,乙队独坐75天可以完成.现在两队合做,但是中途乙队因另有任务调走了假设干天,从开工后40天才把这项工程做完.乙队中途离开多少天？6.有16位教授,有人带1名研究生,也有带2名的,也有带3名的,他们共带了27名研究生,其中带一名研究生的教授人数和带2名、3名研究生的教授人数一样多,问带2名研究生的教授有几人？3.83x4.56+3.83x5.443.7+43.65x4.736.5x0.3713.7x0.255.4x11-5.47、养鸡场的母鸡只数是公鸡的6倍,后来

50、公鸡和母鸡各增加60只,结果母鸡的只数就是公鸡的4倍.原来养鸡场一共养了多少只鸡？8、今年,爸爸的年龄是小明的6倍,再过4年,爸爸的年龄就是小明的4倍.今年小明多少岁？9、原来食堂里存的大米是面粉的4倍,大米和面粉各吃掉80千克,大米的重量是面粉的2倍.食堂里原来存有大米、面粉各多少千克？10、 饲养场的白兔是黑兔的5倍,后来卖掉10只黑兔,买回来20只白兔,现在白兔的只数是黑兔的7倍.饲养场原来养白兔和黑兔各多少只？11、有1800千克的货物,分装在甲乙丙三辆车上.甲车装的千克数正好是乙车的2倍,乙车比丙车多装200千克.甲乙丙三辆车各装货物多少千克？12、三堆货物共1800箱,甲堆的箱数是

51、乙堆的2倍,乙堆的箱数比丙堆少200箱,三堆货物各多少箱？13、甲乙丙三数的和是224,如果甲是乙的3倍,丙是甲的4倍,求甲乙丙三数各是多少？14、把840本书放在书架的三层里,下层放的本数比上层的3倍多5本,中层放的本数是上层的2倍多1本.问：上中下三层各放书多少本？15、甲乙两个书架,甲书架有书600本,从甲书架借出三分之一,从乙书架借出四分之三后,甲书架的书是乙书架的2倍还多150本.乙书架原来有书多少本？16、某校有男生630人,选出男生人数的三分之一和女生的四分之三去排练团体操,剩下的男生人数是女生人数的2倍.这个学校共有学生多少人？17、食堂存有同样重量的大米和面粉,吃掉大米的四分之三和60千克的面粉后,剩下的面粉的重量是大米的3倍.原来存有大米和面粉各有多少千克？18、有两堆水泥,甲堆有4.5吨,甲堆重量的三分之一和乙堆重量的四分之一相等,乙堆有水泥多少吨？19、A站有公共汽车26辆,B站有公共汽车30辆.每小时由A站向B站开出汽车12辆,B站向A站开出汽车8辆,都是经过1小时到达.几小时后B站的公共汽车辆数是A站的3倍？思路：每小时由A站向B站开出汽车12辆,B站向A站开出汽车8辆,实际上就是每隔1小时,A站就减少4辆,而B站就增加4辆