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脱式计算(能简便的用简便方法)

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/15 09:55:51
脱式计算(能简便的用简便方法)
28.8-640%-2.8-4.6                     
7
8
(1)28.8-640%-2.8-4.6
=28.8-6.4-2.8-4.6
=28.8-2.8-(6.4+4.6)
=26-11
=15;
(2)
7
8×370%+5.3×0.875+
7
8
=0.875×3.7+5.3×0.875+0.875
=(3.7+5.3+1)×0.875
=10×0.875
=8.75;
(3)86×75%+14÷
4
3
=86×75%+14×75%
=(86+14)×75%
=100×75%
=75;
(4)
9
32÷[75%-(
7
16-25%)]
=
9
32÷[75%-
3
16]
=
9
32÷
9
16
=
1
2;
(5)(
7
12-37.5%)×24-
5
9.
=(
7
12-
3
8)×24-
5
9.
=
7
12×24-
3
8×24-
5
9
=14-9-
5
9
=4
4
9.