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脱式计算,能进行简便运算的要简便.

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/03 18:42:44
(1)7.6×40.3÷(76×0.8)÷1.25,
=7.6×40.3÷76÷0.8÷1.25,
=7.6÷76÷(0.8×1.25)×40.3,
=0.1×40.3,
=4.03;

(2) 5
1
5 ÷0.65- 1
5
7 ×0.875,
=5.2÷0.65-
12
7 ×
7
8 ,
=8-
3
2 ,
=
13
2 ;

(3)(8.6- 7
4
7 )÷ 2
6
7 +7.64,
=(8
3
5 - 7
4
7 )÷ 2
6
7 +7.64,
=(
43
5 -
53
7 )×
7
20 +7.64,
=
43
5 ×
7
20 -
53
7 ×
7
20 +7.64,
=
301
100 -
53
20 +7.64,
=3.01-2.65+7.64,
=0.36+7.64,
=8;

(4)2.4×[ 2
1
3 ÷(2.4× 1
4
15 -3)],
=2.4×[ 2
1
3 ÷(
76
25 -3)],
=2.4×[ 2
1
3 ÷
1
25 ],
=
12
5 ×
7
3 ×25,
=140;

(5)
456+123×321
123×322+333 +57
1
13 ÷7 ,
=
456+123×321
123×(321+1)+333 +57
1
13 ÷7,
=
456+123×321
123×321+123×1+333 +57
1
13 ÷7,
=
456+123×321
123×321+123+333 +57
1
13 ÷7,
=
456+123×321
123×321+456 +57
1
13 ÷7,
=1+57
1
13 ÷7,
=1+
742
13 ×
1
7 ,
=1+
106
13
=
119
13 .