四年级下册简便运算集锦

1、四年级下册第三单元简便运算举例、练习第一种(例)25x(4+8)=25 x4+15 x8 =100+120=220125x(8+8)(11+25)x8第二种(例)84x101=84 x (100+1 ) =84 x100+84 x1 =8400+84=8484504x2578x10225x204第三种(例)99x64 =(100-1) x64 =100 x64-1 x64 =6400-64 =633699x16638x99999x99第四种(例)99X13+13=(99+1 ) x13=100 x13=130025+199X2532X16+14X3278X4+78X3+78X3第五种(例)25

2、X32X125=(25 X4) X (8 X125)= 100 X1000=100000125X32X888X12572X125第六种(例)3600+25F=3600 + (25 X4) =3600+100=368100+4 H53000+125+81250+25 代第七种1200-624-762100-728-772273-73-27847-527-273=1200- (624+76 )=1200-700=500第八种 278+463+22+37=(278+22 ) + (463+37 )=300+500=800732+580+268425+14+186第九种 214- (86+14) =2

3、14-14-86 =200-86 =114787- (87-29)365- (65+118 )455- (155+230)7第十种871-299=871-300+1 =571+1 =572第十一种178X101-178=( 101-1 ) X178 =100 X178 =17800第十二种 64 + (8X2) =64+8 攵二8攵 =4第十三种625+25=625+5 也 =125+5 =25第十四种100+45-100+45=( 100-100) +( 45+45) =0+90=90第十五种20X4+ 20X4 =(20攵0) X (4X4) =1 X 16=16练习： 169+354+2

4、31+146157-99363-19983X102-83X217X23-23X71300+(13 X5)360-2425+75-25+7525X4+ 25X4987-362-138968-59935X127-35X16-11X35480+(8 X2)270-45423+76-76+77243+85-243+8556X8+56X812X6 12X61347- ( 347+125 )135+236-135+236198 X26148 X56-48 X56210-15199 X37+37215 X63-15 X63101 X22-22203 X14125 X33 X4125 X16 X50365+9

5、97452-398简便运算习题1.加法交换律(a+b=b+a) 如：152+389+348 =152+348+399=500+399=899习题：77+56+23165+477+135154+288+462.加法结合律a+b+c=a+(b+c)如：591 +482 + 118=591 + (482+ 118)=591+600=1191习题：285+147+25399+178+122456+588+412692+325+753.加法交换律、结合律如：32+29 + 68 + 41=32+68+29+41加法交换律=(32+68) + (29+41 )加法结合律=100+70=170习题：( 14

6、8+64 ) + (52+136)650+ (171+350 ) +129128+114+86+1724.乘法交换律a x b=b x a 如：25 X45X4=25 X 4 X 45=100 45=450025 31 4125 27 840 69 255.乘法结合律：a x b x c= a x (b x c)如：78 X125X8125 X 32125 88=78 X (125 X8)=78 1000=7800052 25 4=125 X (8X4)=125 8 4=4000125 7225X3225 X44125X486 .乘法交换律、结合律如：125 X 4X8X25=125 X8X4

7、X25 乘法交换律=(125X8) X (4X25)乘法结合律= 1000 X 100=100000习题：125 X 25X327 .乘法分配律：a x (b+c)=a x b+a x c如：27 X 57+27 X 43 =27 X (57+43) =27 100 =2700习题：67X34+67 X6627X 99+27=27 X (99+1) =27 100 =27002799=27 X (100-1 ) =27 100-27 1 =2673127X43-27 X4327X101-272710167 21+67 78+6767 23+67 78+67-6712 340+6612025 4

8、4125 8885 10269 10278 9865+65 995 87+87+87 4如：781-178-122721-488-121745- (245+188 )=781- (178+122 )=721-121-488=745-245-188=781-300=600-488=500-188=481=112=312习题：456-273-127623-169-2238.减法运算性质；a-b-c=a-(b+c)=a-c-b553- (289+153)772-456+228689- (289-153 )136-88+164-1129.除法运算性质;a b- -e=a 甘x c)=a e -b 如：

9、720 +36 e=720- ( 36 X2)=720 +72=103900 + (39X4)习题：2700 +25 + 45600 +25 - 56#怎样简便就怎样算、355+260+140+24538 X99 + 38368+156+344+13296X58+96X42368+156+344+13296 58+96 42四、789-136-6488 125036 88+36 15-108综合练习简便运算98X10148X125645-180-2453500+14 W125 47 86300 + (63X5)125 47 86300 + (63X5)132 29+13248X125175 X

10、56 + 25 X5650 25 20 407200+25+4482 - (182+50)7200-25F482 -(182+50)98X83+166125X32X12544 25135 27+135 72+13544 25135 27+135 72+1353700+4攵517五、355+260+140+24598X10148X125645-180-24538 X99 + 383500+14 W175 X56 + 25 X56125 X32 X25六、98+265+202273-73-27250 13 43200+4攵588 12599X38+3817 X23-23 X772 125七、64X

11、15-5 6425X (12W0)99 56+562182-1655-3453200 F 攵5298 X99 + 298(40 + 8) 2597 8 125八、355+260+140+245102X992X125645-180-245382 X 101-3824 60 50 835 8+35 6-4 35125 32九、25X461015699 261022 478 422987 (287 + 135)478 -256-144672 36+6436+64-36 + 64十、487 287 139 61 500 257 34 1432000 -368-1321814 378 42289 X 9

12、9 + 89155 + 264 + 36 + 4425 X (20 + 4)88 X225 + 225 X121、698-291 -9568(68 + 178)561 -19+58382 + 165 + 35-82236+189+64759-126-25925 79 4569-256-44216+89+1157 X125 X81050 T5H169X123 23X16937 99+37129X101129149X69 149+149X3256X51+56X48+56十三、125X25X3224 25125 48514+189 214369256+15656 25 4 12524X73+26X2

13、4109+ (291176)十四、16X98+32512+ (373212)228+ (72+189 )169+199586 X9957525027537X2121 X1221125 X88 X25、计算(能简便就简便)、85+14X (14+208+ 26)21+(327-23)勺9539-513+(378 勺 4)34-3094 勺 7 勺 319+(253-22) 2150+20X28-42(23+23) 24-597(110-10) 10-1045-24+14 X14二、304-275+(275 笠5)(70+10) (18-10)120-12X18-5444+16X15-32(10-

14、100 -10) M1(53-588 N1)刈6(60+10) (17-10)17+(233-43) 10100-10X10-60三、424-475+19 X1622+(374-10) 26(245-11) 48-1122-(10+100 10)(252-14) 17-1035-13+10 X15(346-10) 16-12215-198 W121 T1)(45-651 1) 33四、19+192-12-10572-22X23-15819+56-1224-34(714-12) 27-1914+(21-19) X418-(13+15) 262736+(43-20) 23(227+11)中31-1

15、4)36+19X14-23五、828+23X12-4818-15+10X18(31-154 勺1)X2(1369-37) 37-32160(22-12) 22357 攵1X13-213985-728 攵6 X35(438-39) 2-1-12(20+18) X1-239六、50+ 160F0(58+370 ) + (64-45)120-144 勺 8+3578X501440+123856+16+85X164000 + (16+832+13)(326+95X 25)37(7236+18 228) 28(4275-24 X75)攵5七、178-145+5X6+42420+580-64X21 攵88

16、12-700 + (9+31X11 )50 + 16040=54120-144 T8+35=147(58+37) + (64-9 5)95 + (64-45)178-145 -5 6+42120-36 4-18+35八、58 X58 + 58X423874 - (874+ 1000136X101-136329-38-62347-129-1474600 +25 + 46000 +125 + 825 X 125X32360 - 45九、44X25591 +482 + 11899 X I26125 X 15X8986+1999473+79-6380X501-8076+38+24+162199 X99

17、+199十、25 X125X4X840X9X25X855 25+25 452332+129+268+71438+126+162+67455 X 55+45 X 558X6X 125X58 X 135+8 X6556 X 37-56 X 26-56I一、45X12+55 X1242 X 9+58 X 955 X 45+45 X 4518 X27+18 X2358 X 137-58 X3778 X 8-28 X 87X69+7X2136 X 27+27 X 6499 X64+64十二、250 X 3648 X 250202 X 45125 X 32199X50301 X 3045X201-4549 X49+4925X (8+40 )十三、8X6X 1257 X 4 X 250250 X 3 X 499X199+9935X401-3539 X 101-39十四、25X3