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下面各题你认为怎样简便就怎样算.

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/13 16:18:58
(1)
5
7 ÷(5-3×
2
3 ),
=
5
7 ÷(5-2),
=
5
7 ÷3,
=
5
7 ×
1
3 ,
=
5
21 ;

(2)84×0.25+
1
4 ×16,
=84×0.25+0.25×16,
=(84+16)×0.25,
=100×0.25,
=25;

(3)48×(
1
3 -
1
2 +
1
4 ),
=48×
1
3 -48×
1
2 +48×
1
4 ,
=16-24+12,
=4;

(4)
1
2 ÷
2
5 -
2
3 ×
7
10 ,
=
1
2 ×
5
2 -
2
3 ×
7
10 ,
=
5
4 -
7
15 ,
=
47
60 ;

(5)7.8×101,
=7.8×(100+1),
=780+7.8,
=787.8;

(6)(1-0.8×
3
4 )÷
4
5 ,
=(1-0.6)÷
4
5 ,
=0.4×
5
4 ,
=0.5.