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。