脱式计算(能简便的用简便方法) 28.8-640%-2.8-4.6 7/8×370%+5.3×0.875+7/8 86×75%+14÷4/3 9/32÷[75%-(7/16-25%)] (7/12-37.5%)×24-5/9.

问题描述:

脱式计算(能简便的用简便方法)
28.8-640%-2.8-4.6                     

7
8
×370%+5.3×0.875+
7
8

86×75%+14÷
4
3

9
32
÷[75%-(
7
16
-25%)]
7
12
-37.5%)×24-
5
9

(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