2024年8月14日发(作者:度星阑)
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
4
)
655 +
(
186 -155
)
(
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8月14日发(作者:度星阑)
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
4
)
655 +
(
186 -155
)
(
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
。