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合理、灵活地计算.14.15-(778-61720)-2.1251837×25+237×195(111+999)÷[56×(37-38)]6.45×0.75+4.55×75%-3

题目详情
合理、灵活地计算.
14.15-(7
7
8
-6
17
20
)-2.125
18
37
×
2
5
+
2
37
×
19
5

(111+999)÷[56×(
3
7
-
3
8
)]
6.45×0.75+4.55×75%-
3
4
▼优质解答
答案和解析
(1)14.15-(7
7
8
-6
17
20
)-2.125,
=14.15-7
7
8
+6
17
20
-2.125,
=(14.15+6.85)-(7.875+2.125),
=21-10,
=11;

(2)
18
37
×
2
5
+
2
37
×
19
5

=
18
37
×
2
5
+
19
37
×
2
5

=(
18
37
+
19
37
)×
2
5

=1×
2
5

=
2
5


(3)(111+999)÷[56×(
3
7
-
3
8
)],
=1110÷[56×
3
7
-56×
3
8
],
=1110÷(24-21),
=1110÷3,
=370;

(4)6.45×0.75+4.55×75%-
3
4

=6.45×0.75+4.55×0.75-0.75×1,
=(6.45+4.55-1)×0.75,
=10×0.75,
=7.5.