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人教版四年级数学下册第三单元简便运算专项训练【含答案】

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2024年10月18日发(作者:荤清宁)

人教版四年级数学下册第三单元 简便运算 专项训练

一、计算题(共33题;共395分)

1.直接写出得数。

34+27+16= 18+55+45= 25×13×4=

(8+4)×5= 19×6+11×6= 36×64+36×36=

2.脱式计算,标*的题要用运算律简算.

(1)[192÷(96-72)]×28 (2)*257+396+43

(3)*136×25×4 (4)*78×102-78×2

3.用简便方法计算。

(1)347-(247+75) (2)48-25-75+152 (3)57+138+43

4.脱式计算,能简算的要简算。

①36×64+36×36 ②125×4×8×25 ③(927-583)÷43×75

④12×999 ⑤88×125 ⑥15×[(825-153)÷21]

5.计算下面各题,能简算的要简算。

(1)230×[84÷(240-228)] (2)340-240÷20×5

(3)32×17×25×125 (4)136×68-68×36

6.下面各题怎样简便就怎样算。

(1)307-98 (2)145+39+161+55

(3)540÷30×140 (4)275-400÷16

7.用自己喜欢的方法计算。

(1)102×36 (2)383+468+17+132

(3)165÷[3×(47-42)] (4)98+360÷(30-26)

8.简便计算。

(1)8×(125×23) (2)143×52-52×43 (3)202×36

9.用递等式计算,能简算的就简算。

(1)559-32×(280÷40) (2)57×15+43×15

(3)125-39-61 (4)864÷[(26-23)×12]

10.下面各题,用你喜欢的方法计算,要写出计算过程(一步计算可用竖式计算)

①944÷16 ②158×99 ③[196-(96+4)]÷6

④27×125×8 ⑤123×78+123×22 ⑥(43+104+57)÷17

11.用递等式计算。

(1)672÷[14×(25-22)] (2)125×9×8 (3)169×45+169×54+169

12.用简便方法计算。

(1)8×62×125 (2)102×36 (3)105×99-5×99 (4)348-69-31

13.怎样简便就怎样计算。

(1)247+35+165-47 (2)72×28+72×72 (3)460×(80-720÷9)

14.用你喜欢的方法计算,能简算的要简算。

①101×83 ②97-12×6+43 ③67×53+67×47

④125×23×8 ⑤54×99+54 ⑥540÷[(51-48)×12]

15.怎样简便就怎样计算。

(1)25×47-25×3 (2)48×18+14×54

16.怎样简便就怎样计算。

①352+39-152 ②50×28×4 ③604-135-65

④3600÷5÷18 ⑤99×15+15 ⑥104×45-45×4

17.怎样简便就怎样计算。

①64+357+136 ②264-(38+64) ③407-107-55

④85-39+105 ⑤245-65+35 ⑥366-43-57+34

18.用你认为最简便的方法计算。

①45×14×2 ②36×15+64×15 ③125×18

④1200÷24÷5 ⑤55×104 ⑥75×40×6

19.用简便方法计算:109×99

20.怎样简便就怎样计算。

(1)652+139+248 (2)46+235+54+65

21.怎样简便就怎样计算。

①125×32 ②44×25 ③360÷12÷5

④800÷25÷4 ⑤4500÷15÷3 ⑥350×18

22.用加法交换律或加法结合律计算。

(1)112+59+38 (2)73+45+65

(3)305+58+25 (4)(259+63)+137

23.用乘法分配律计算。

①(25+11)×4 ②15×(8+6) ③(125-9)×6

④18×35+32×35 ⑤56×44+44×44

24.能简便的用简便方法计算。

(1)25×3.2×4 (2)38×45+62×45 (3)23×101

155)

4)655 +(186 -(

25.选择合适的方法计算。

(1)28×203 (2)125×32 (3)448÷89 (4)490÷35

26.用简便方法计算。

(1)25×7×4 (2)132×18-18×32 (3)540÷45

27.简便计算。

(1)2300-165-35 (2)125×72×8 (3)45×101-45

28.用简便方法计算,并写出简便过程。

①1.35+5.64+8.65+4.36 ②33000÷125÷8 ③57×98+57×2

④125×25×32 ⑤93×101-93 ⑥268-73-27

29.脱式计算,怎样简便就怎样计算。

(1)3.9+4.08+3.92+1.1 (2)17×23-23×7

(3)32×25 (4)32×[275÷(23+32)]

30.用简便方法计算。

(1)126×9+174×9 (2)24.9-(4.9+6.57)

31.用简便方法计算,请写清楚简算步骤。

①285+286+114+15 ②13.75-(3.75+8.5)

3)125×32×25 (

③39×56+56×61 ④74×125×8

⑤1.29+3.7+0.71+6.3 ⑥35×101

32.用简便方法计算下面各题。

①72+238+28 ②125×48 ③101×67

④37×46+46×63 ⑤938-263-537

33.怎样算简便就怎样算。

①548+302 ②25×44 ③330÷5÷2

④71+55+129+45 ⑤57×39+61×57 ⑥64×101-64

答案解析部分

一、计算题

1. 34+27+16=77 18+55+45=118 25×13×4=1300

(8+4)×5=60 19×6+11×6=180 36×64+36×36=3600

2. (1)[192÷(96-72)]×28

= [192÷24]×28

=8×28

=224

(2)257+396+43

=257+43+396

=300+396

=696

(3)136×25×4

=136×(25×4)

=136×100

=13600

(4)78×102-78×2

=78×(102-2)

=78×100

=7800

3. (1)347-(247+75)

=347-247-75

=100-75

=25

(2)48-25-75+152

=48+152-25-75

=(48+152)-(25+75)

=200-100

=100

(3)57+138+43

=57+43+138

=100+138

=238

4. ①36×64+36×36

=36×(64+36)

=36×100

=3600

②125×4×8×25

=(125×8)×(4×25)

=1000×100

=③(927-583)÷43×75

=344÷43×75

=8×75

=600

④12×999

=12×(1000-1)

=12×1000-12

=12000-12

=11988

⑤88×125

=(80+8)×125

=80×125+8×125

=10000+1000

=11000

⑥15×[(825-153)÷21]

=15×(672÷21)

=15×32

=480

5. (1)230×[84÷(240-228)]

=230×[84÷12]

=230×7

=1610

(2)340-240÷20×5

=340-12×5

=340-60

=280

(3)32×17×25×125

=17×(4×25)×(8×125)

=17×100×1000

=(4)136×68-68×36

=(136-36)×68

=100×68

=6800

6. (1)307-98

=307-(100-2)

=307-100+2

=209

(2)145+39+161+55

=(145+55)+(39+161)

=200+200

=400

(3)540÷30×140

=18×140

=2520

(4)275-400÷16

=275-25

=250

7. (1)102×36

=(100+2)×36

=100×36+2×36

=3600+72

=3672

(2)383+468+17+132

=(383+17)+(468+132)

=400+600

=1000

(3)165÷[3×(47-42)

=165÷[3×5]

=165÷15

=11

(4)98+360÷(30-26)

=98+360÷4

=98+90

=188

8. (1)8×(125×23)

=8×125×23

=1000×23

=23000

(2)143×52-52×43

=52×(143-43)

=52×100

=5200

(3)202×36

=(200+2)×36

=200×36+2×36

=7200+72

=7272

9. (1)559-32×(280÷40)

=559-32×7

=559-224

=335

(2)57×15+43×15

=(57+43)×15

=100×15

=1500

(3)125-39-61

=125-(39+61)

=125-100

=25

(4)864÷[(26-23)×12]

=864÷[3×12]

=864÷36

=24

10. ①944÷16=59

②158×99

=158×(100-1)

=158×100-158

=15800-158

=15642

③[196-(96+4)]÷6

=(196-100)÷6

=96÷6

=16

④27×125×8

=125×8×27

=1000×27

=27000

⑤123×78+123×22

=123×(78+22)

=123×100

=12300

⑥(43+104+57)÷17

=(43+57+104)÷17

=204÷17

=12

11. (1)672÷[14×(25-22)]

=672÷(14×3)

=672÷42

=16

(2)125×9×8

=(125×8)×9

=1000×9

=9000

(3)169×45+169×54+169

=169×(45+54+1)

=169×100

=16900

12. (1)8×62×125

=8×125×62

=1000×62

=62000

(2)102×36

=100×36+2×36

=3600+72

=3672

(3)105×99-5×99

=(105-5)×99

=100×99

=9900

(4)348-69-31

=348-(69+31)

=348-100

=248

13. (1)247+35+165-47

=(247-47)+(35+165)

=200+200

=400

(2)72×28+72×72

=72×(28+72)

=72×100

=7200

(3)460×(80-720÷9)

=460×(80-80)

=460×0

=0

14. ①101×83

=(100+1)×83

=83×100+83

=8300+83

=8383

②97-12×6+43

=97-72+43

=5+43

=48

③67×53+67×47

=67×(53+47)

=67×100

=6700

④125×23×8

=125×8×23

=1000×23

=23000

⑤54×99+54

=54×(99+1)

=54×100

=5400

⑥540÷[(51-48)×12]

=540÷(3×12)

=540÷36

=15

15. (1)25×47-25×3

=25×(47-3)

=25×44

=25×(40+4)

=25×40+25×4

=1000+100

=1100

(2)48×18+14×54

=48×18+14×3×18

=48×18+42×18

=(48+42)×18

=90×18

=1620

16. ①352+39-152

=352-152+39

=200+39

=239

②50×28×4

=50×4×28

=200×28

=5600

③604-135-65

=604-(135+65)

=604-200

=404

④3600÷5÷18

=3600÷(5×18)

=3600÷90

=40

⑤99×15+15

=99×15+15×1

=15×(99+1)

=15×100

=1500

⑥104×45-45×4

=(104-4)×45

=100×45

=4500

17. ①64+357+136

=64+136+357

=200+357

=557

②264-(38+64)

=264-64-38

=200-38

=162

③407-107-55

=300-55

=245

④85-39+105

=85+105-39

=190-39

=151

⑤245-65+35

=245+35-65

=280-65

=215

⑥366-43-57+34

=366+34-(43+57)

=400-100

=300

18. ①45×14×2

=45×2×14

=90×14

=1260

②36×15+64×15

=(36+64)×15

=100×15

=1500

③125×18

=125×(10+8)

=125×10+125×8

=1250+1000

=2250

④1200÷24÷5

=1200÷(24×5)

=1200÷120

=10

⑤55×104

=55×(100+4)

=55×100+55×4

=5500+220

=5720

⑥75×40×6

=3000×6

=18000

19. 109×99

=109×(100-1)

=109×100-109×1

=10900-109

=10791。

20. (1)652+139+248

=652+248+139

=900+139

=1039

(2)46+235+54+65

=(46+54)+(235+65)

=100+300

=400

21. 解:①125×32

=125×8×4

=1000×4

=4000

②44×25

=11×(4×25)

=11×100

=1100

③360÷12÷5

=360÷(12×5)

=360÷60

=6

④800÷25÷4

=800÷(25×4)

=800÷100

=8

⑤4500÷15÷3

=4500÷(15×3)

=4500÷45

=100

⑥350×18

=350×2×9

=700×9

=6300

22. (1)112+59+38

=112+38+59

=150+59

=219

(2)73+45+65

=73+(45+64)

=73+110

=183

(3)305+58+25

=305+25+58

=330+58

=388

(4)(259+63)+137

=259+(63+137)

=259+200

=459

23. ①(25+11)×4

=25×4+11×4

=100+44

=144

②15×(8+6)

=15×8+15×6

=120+90

=210

③(125-9)×6

=125×6-9×6

=150-56

=94

④18×35+32×35

=(18+32)×35

=50×35

=1750

⑤56×44+44×44

=(56+44)×44

=100×44

=4400

24. (1)25×3.2×4

= 25×4×3.2

=100×3.2

=320

(2)38×45+62×45

=(38+62)×45

=100×45

=4500

(3)23×101

=23×(100+1)

=23×100+23×1

=2300+23

=2323

(4)655 +(186 -155)

=655-155+186

=500+186

=686

25. (1)28×203

=28×(200+3)

=28×200+28×3

=5600+84

=5684

(2)125×32

=125×8×4

=1000×4

=4000

(3)3

(4)490÷35

=490÷(7×5)

=490÷7÷5

=70÷5

=14

26. (1)25×7×4

=25×4×7

=100×7

=700

(2)132×18-18×32

=(132-32)×18

=100×18

=1800

(3)540÷45

=540÷9÷5

=60÷5

=12

27. (1)2300-165-35

=2300-(165+35)

=2300-200

=2100

(2)125×72×8

=125×8×72

=1000×72

=72000

(3)45×101-45

=45×(101-1)

=45×100

=4500

28. ①1.35+5.64+8.65+4.36

=(1.35+8.65)+(5.64+4.36)

=10+10

=20;

②33000÷125÷8

=33000÷(125×8)

=33000÷1000

=33;

③57×98+57×2

=57×(98+2)

=57×100

=5700;

④125×25×32

=125×25×8×4

=(125×8)×(25×4)

=1000×100

=;

⑤93×101-93

=93×(101-1)

=93×100

=9300;

⑥268-73-27

=268-(73+27)

=268-100

=168。

29. (1)3.9+4.08+3.92+1.1

=(3.9+1.1)+(4.08+3.92)

=5+8

=13

(2)17×23-23×7

=(17-7)×23

=10×23

=230

(3)32×25

=8×4×25

=8×(4×25)

=8×100

=800

(4)32×[275÷(23+32)]

=32×[275÷55]

=32×5

=160

30. (1)126×9+174×9

=(126+174)×9

=300×9

=2700

(2)24.9-(4.9+6.57)

=24.9-4.9-6.57

=20-6.57

=13.43

(3)125×32×25

=125×8×4×25

=(125×8)×(4×25)

=1000×100

=

31. ①285+286+114+15

=(285+15)+(286+114)

=300+400

=700

②13.75-(3.75+8.5)

=(13.75-3.75)-8.5

=10-8.5

=105

③39×56+56×61

=(39+61)×56

=100×56

=5600

④74×125×8

=74×(125×8)

=74×1000

=74000

⑤1.29+3.7+0.71+6.3

=(1.29+0.71)+(3.7+6.3)

=2+10

=12

⑥35×101

=35×(100+1)

=35×100+35

=3535

32. ①72+238+28

=238+(72+28)

=238+100

=338

②125×48

=(125×8)×6

=1000×6

=6000

③101×67

=(100+1)×67

=100×67+67

=6700+67

=6767

④37×46+46×63

=(37+63)×46

=100×46

=4600

⑤938-263-537

=938-(263+537)

=938-800

=138

33. ①548+302

=548+300+2

=848+2

=850;

②25×44

=25×(40+4)

=25×40+25×4

=1000+100

=1100;

③330÷5÷2

=330÷(5×2)

=330÷10

=33;

④ 71+55+129+45

=(71+129)+(55+45)

=200+100

=300;

⑤ 57×39+61×57

=57×(39+61)

=57×100

=5700;

⑥ 64×101-64

=64×(101-1)

=64×100

=6400。

2024年10月18日发(作者:荤清宁)

人教版四年级数学下册第三单元 简便运算 专项训练

一、计算题(共33题;共395分)

1.直接写出得数。

34+27+16= 18+55+45= 25×13×4=

(8+4)×5= 19×6+11×6= 36×64+36×36=

2.脱式计算,标*的题要用运算律简算.

(1)[192÷(96-72)]×28 (2)*257+396+43

(3)*136×25×4 (4)*78×102-78×2

3.用简便方法计算。

(1)347-(247+75) (2)48-25-75+152 (3)57+138+43

4.脱式计算,能简算的要简算。

①36×64+36×36 ②125×4×8×25 ③(927-583)÷43×75

④12×999 ⑤88×125 ⑥15×[(825-153)÷21]

5.计算下面各题,能简算的要简算。

(1)230×[84÷(240-228)] (2)340-240÷20×5

(3)32×17×25×125 (4)136×68-68×36

6.下面各题怎样简便就怎样算。

(1)307-98 (2)145+39+161+55

(3)540÷30×140 (4)275-400÷16

7.用自己喜欢的方法计算。

(1)102×36 (2)383+468+17+132

(3)165÷[3×(47-42)] (4)98+360÷(30-26)

8.简便计算。

(1)8×(125×23) (2)143×52-52×43 (3)202×36

9.用递等式计算,能简算的就简算。

(1)559-32×(280÷40) (2)57×15+43×15

(3)125-39-61 (4)864÷[(26-23)×12]

10.下面各题,用你喜欢的方法计算,要写出计算过程(一步计算可用竖式计算)

①944÷16 ②158×99 ③[196-(96+4)]÷6

④27×125×8 ⑤123×78+123×22 ⑥(43+104+57)÷17

11.用递等式计算。

(1)672÷[14×(25-22)] (2)125×9×8 (3)169×45+169×54+169

12.用简便方法计算。

(1)8×62×125 (2)102×36 (3)105×99-5×99 (4)348-69-31

13.怎样简便就怎样计算。

(1)247+35+165-47 (2)72×28+72×72 (3)460×(80-720÷9)

14.用你喜欢的方法计算,能简算的要简算。

①101×83 ②97-12×6+43 ③67×53+67×47

④125×23×8 ⑤54×99+54 ⑥540÷[(51-48)×12]

15.怎样简便就怎样计算。

(1)25×47-25×3 (2)48×18+14×54

16.怎样简便就怎样计算。

①352+39-152 ②50×28×4 ③604-135-65

④3600÷5÷18 ⑤99×15+15 ⑥104×45-45×4

17.怎样简便就怎样计算。

①64+357+136 ②264-(38+64) ③407-107-55

④85-39+105 ⑤245-65+35 ⑥366-43-57+34

18.用你认为最简便的方法计算。

①45×14×2 ②36×15+64×15 ③125×18

④1200÷24÷5 ⑤55×104 ⑥75×40×6

19.用简便方法计算:109×99

20.怎样简便就怎样计算。

(1)652+139+248 (2)46+235+54+65

21.怎样简便就怎样计算。

①125×32 ②44×25 ③360÷12÷5

④800÷25÷4 ⑤4500÷15÷3 ⑥350×18

22.用加法交换律或加法结合律计算。

(1)112+59+38 (2)73+45+65

(3)305+58+25 (4)(259+63)+137

23.用乘法分配律计算。

①(25+11)×4 ②15×(8+6) ③(125-9)×6

④18×35+32×35 ⑤56×44+44×44

24.能简便的用简便方法计算。

(1)25×3.2×4 (2)38×45+62×45 (3)23×101

155)

4)655 +(186 -(

25.选择合适的方法计算。

(1)28×203 (2)125×32 (3)448÷89 (4)490÷35

26.用简便方法计算。

(1)25×7×4 (2)132×18-18×32 (3)540÷45

27.简便计算。

(1)2300-165-35 (2)125×72×8 (3)45×101-45

28.用简便方法计算,并写出简便过程。

①1.35+5.64+8.65+4.36 ②33000÷125÷8 ③57×98+57×2

④125×25×32 ⑤93×101-93 ⑥268-73-27

29.脱式计算,怎样简便就怎样计算。

(1)3.9+4.08+3.92+1.1 (2)17×23-23×7

(3)32×25 (4)32×[275÷(23+32)]

30.用简便方法计算。

(1)126×9+174×9 (2)24.9-(4.9+6.57)

31.用简便方法计算,请写清楚简算步骤。

①285+286+114+15 ②13.75-(3.75+8.5)

3)125×32×25 (

③39×56+56×61 ④74×125×8

⑤1.29+3.7+0.71+6.3 ⑥35×101

32.用简便方法计算下面各题。

①72+238+28 ②125×48 ③101×67

④37×46+46×63 ⑤938-263-537

33.怎样算简便就怎样算。

①548+302 ②25×44 ③330÷5÷2

④71+55+129+45 ⑤57×39+61×57 ⑥64×101-64

答案解析部分

一、计算题

1. 34+27+16=77 18+55+45=118 25×13×4=1300

(8+4)×5=60 19×6+11×6=180 36×64+36×36=3600

2. (1)[192÷(96-72)]×28

= [192÷24]×28

=8×28

=224

(2)257+396+43

=257+43+396

=300+396

=696

(3)136×25×4

=136×(25×4)

=136×100

=13600

(4)78×102-78×2

=78×(102-2)

=78×100

=7800

3. (1)347-(247+75)

=347-247-75

=100-75

=25

(2)48-25-75+152

=48+152-25-75

=(48+152)-(25+75)

=200-100

=100

(3)57+138+43

=57+43+138

=100+138

=238

4. ①36×64+36×36

=36×(64+36)

=36×100

=3600

②125×4×8×25

=(125×8)×(4×25)

=1000×100

=③(927-583)÷43×75

=344÷43×75

=8×75

=600

④12×999

=12×(1000-1)

=12×1000-12

=12000-12

=11988

⑤88×125

=(80+8)×125

=80×125+8×125

=10000+1000

=11000

⑥15×[(825-153)÷21]

=15×(672÷21)

=15×32

=480

5. (1)230×[84÷(240-228)]

=230×[84÷12]

=230×7

=1610

(2)340-240÷20×5

=340-12×5

=340-60

=280

(3)32×17×25×125

=17×(4×25)×(8×125)

=17×100×1000

=(4)136×68-68×36

=(136-36)×68

=100×68

=6800

6. (1)307-98

=307-(100-2)

=307-100+2

=209

(2)145+39+161+55

=(145+55)+(39+161)

=200+200

=400

(3)540÷30×140

=18×140

=2520

(4)275-400÷16

=275-25

=250

7. (1)102×36

=(100+2)×36

=100×36+2×36

=3600+72

=3672

(2)383+468+17+132

=(383+17)+(468+132)

=400+600

=1000

(3)165÷[3×(47-42)

=165÷[3×5]

=165÷15

=11

(4)98+360÷(30-26)

=98+360÷4

=98+90

=188

8. (1)8×(125×23)

=8×125×23

=1000×23

=23000

(2)143×52-52×43

=52×(143-43)

=52×100

=5200

(3)202×36

=(200+2)×36

=200×36+2×36

=7200+72

=7272

9. (1)559-32×(280÷40)

=559-32×7

=559-224

=335

(2)57×15+43×15

=(57+43)×15

=100×15

=1500

(3)125-39-61

=125-(39+61)

=125-100

=25

(4)864÷[(26-23)×12]

=864÷[3×12]

=864÷36

=24

10. ①944÷16=59

②158×99

=158×(100-1)

=158×100-158

=15800-158

=15642

③[196-(96+4)]÷6

=(196-100)÷6

=96÷6

=16

④27×125×8

=125×8×27

=1000×27

=27000

⑤123×78+123×22

=123×(78+22)

=123×100

=12300

⑥(43+104+57)÷17

=(43+57+104)÷17

=204÷17

=12

11. (1)672÷[14×(25-22)]

=672÷(14×3)

=672÷42

=16

(2)125×9×8

=(125×8)×9

=1000×9

=9000

(3)169×45+169×54+169

=169×(45+54+1)

=169×100

=16900

12. (1)8×62×125

=8×125×62

=1000×62

=62000

(2)102×36

=100×36+2×36

=3600+72

=3672

(3)105×99-5×99

=(105-5)×99

=100×99

=9900

(4)348-69-31

=348-(69+31)

=348-100

=248

13. (1)247+35+165-47

=(247-47)+(35+165)

=200+200

=400

(2)72×28+72×72

=72×(28+72)

=72×100

=7200

(3)460×(80-720÷9)

=460×(80-80)

=460×0

=0

14. ①101×83

=(100+1)×83

=83×100+83

=8300+83

=8383

②97-12×6+43

=97-72+43

=5+43

=48

③67×53+67×47

=67×(53+47)

=67×100

=6700

④125×23×8

=125×8×23

=1000×23

=23000

⑤54×99+54

=54×(99+1)

=54×100

=5400

⑥540÷[(51-48)×12]

=540÷(3×12)

=540÷36

=15

15. (1)25×47-25×3

=25×(47-3)

=25×44

=25×(40+4)

=25×40+25×4

=1000+100

=1100

(2)48×18+14×54

=48×18+14×3×18

=48×18+42×18

=(48+42)×18

=90×18

=1620

16. ①352+39-152

=352-152+39

=200+39

=239

②50×28×4

=50×4×28

=200×28

=5600

③604-135-65

=604-(135+65)

=604-200

=404

④3600÷5÷18

=3600÷(5×18)

=3600÷90

=40

⑤99×15+15

=99×15+15×1

=15×(99+1)

=15×100

=1500

⑥104×45-45×4

=(104-4)×45

=100×45

=4500

17. ①64+357+136

=64+136+357

=200+357

=557

②264-(38+64)

=264-64-38

=200-38

=162

③407-107-55

=300-55

=245

④85-39+105

=85+105-39

=190-39

=151

⑤245-65+35

=245+35-65

=280-65

=215

⑥366-43-57+34

=366+34-(43+57)

=400-100

=300

18. ①45×14×2

=45×2×14

=90×14

=1260

②36×15+64×15

=(36+64)×15

=100×15

=1500

③125×18

=125×(10+8)

=125×10+125×8

=1250+1000

=2250

④1200÷24÷5

=1200÷(24×5)

=1200÷120

=10

⑤55×104

=55×(100+4)

=55×100+55×4

=5500+220

=5720

⑥75×40×6

=3000×6

=18000

19. 109×99

=109×(100-1)

=109×100-109×1

=10900-109

=10791。

20. (1)652+139+248

=652+248+139

=900+139

=1039

(2)46+235+54+65

=(46+54)+(235+65)

=100+300

=400

21. 解:①125×32

=125×8×4

=1000×4

=4000

②44×25

=11×(4×25)

=11×100

=1100

③360÷12÷5

=360÷(12×5)

=360÷60

=6

④800÷25÷4

=800÷(25×4)

=800÷100

=8

⑤4500÷15÷3

=4500÷(15×3)

=4500÷45

=100

⑥350×18

=350×2×9

=700×9

=6300

22. (1)112+59+38

=112+38+59

=150+59

=219

(2)73+45+65

=73+(45+64)

=73+110

=183

(3)305+58+25

=305+25+58

=330+58

=388

(4)(259+63)+137

=259+(63+137)

=259+200

=459

23. ①(25+11)×4

=25×4+11×4

=100+44

=144

②15×(8+6)

=15×8+15×6

=120+90

=210

③(125-9)×6

=125×6-9×6

=150-56

=94

④18×35+32×35

=(18+32)×35

=50×35

=1750

⑤56×44+44×44

=(56+44)×44

=100×44

=4400

24. (1)25×3.2×4

= 25×4×3.2

=100×3.2

=320

(2)38×45+62×45

=(38+62)×45

=100×45

=4500

(3)23×101

=23×(100+1)

=23×100+23×1

=2300+23

=2323

(4)655 +(186 -155)

=655-155+186

=500+186

=686

25. (1)28×203

=28×(200+3)

=28×200+28×3

=5600+84

=5684

(2)125×32

=125×8×4

=1000×4

=4000

(3)3

(4)490÷35

=490÷(7×5)

=490÷7÷5

=70÷5

=14

26. (1)25×7×4

=25×4×7

=100×7

=700

(2)132×18-18×32

=(132-32)×18

=100×18

=1800

(3)540÷45

=540÷9÷5

=60÷5

=12

27. (1)2300-165-35

=2300-(165+35)

=2300-200

=2100

(2)125×72×8

=125×8×72

=1000×72

=72000

(3)45×101-45

=45×(101-1)

=45×100

=4500

28. ①1.35+5.64+8.65+4.36

=(1.35+8.65)+(5.64+4.36)

=10+10

=20;

②33000÷125÷8

=33000÷(125×8)

=33000÷1000

=33;

③57×98+57×2

=57×(98+2)

=57×100

=5700;

④125×25×32

=125×25×8×4

=(125×8)×(25×4)

=1000×100

=;

⑤93×101-93

=93×(101-1)

=93×100

=9300;

⑥268-73-27

=268-(73+27)

=268-100

=168。

29. (1)3.9+4.08+3.92+1.1

=(3.9+1.1)+(4.08+3.92)

=5+8

=13

(2)17×23-23×7

=(17-7)×23

=10×23

=230

(3)32×25

=8×4×25

=8×(4×25)

=8×100

=800

(4)32×[275÷(23+32)]

=32×[275÷55]

=32×5

=160

30. (1)126×9+174×9

=(126+174)×9

=300×9

=2700

(2)24.9-(4.9+6.57)

=24.9-4.9-6.57

=20-6.57

=13.43

(3)125×32×25

=125×8×4×25

=(125×8)×(4×25)

=1000×100

=

31. ①285+286+114+15

=(285+15)+(286+114)

=300+400

=700

②13.75-(3.75+8.5)

=(13.75-3.75)-8.5

=10-8.5

=105

③39×56+56×61

=(39+61)×56

=100×56

=5600

④74×125×8

=74×(125×8)

=74×1000

=74000

⑤1.29+3.7+0.71+6.3

=(1.29+0.71)+(3.7+6.3)

=2+10

=12

⑥35×101

=35×(100+1)

=35×100+35

=3535

32. ①72+238+28

=238+(72+28)

=238+100

=338

②125×48

=(125×8)×6

=1000×6

=6000

③101×67

=(100+1)×67

=100×67+67

=6700+67

=6767

④37×46+46×63

=(37+63)×46

=100×46

=4600

⑤938-263-537

=938-(263+537)

=938-800

=138

33. ①548+302

=548+300+2

=848+2

=850;

②25×44

=25×(40+4)

=25×40+25×4

=1000+100

=1100;

③330÷5÷2

=330÷(5×2)

=330÷10

=33;

④ 71+55+129+45

=(71+129)+(55+45)

=200+100

=300;

⑤ 57×39+61×57

=57×(39+61)

=57×100

=5700;

⑥ 64×101-64

=64×(101-1)

=64×100

=6400。

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