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下面各题怎样简便就怎样算.87×386517÷9+19×1217215÷[1-(15+13)]5.37-1.47-2.53157+1112+67+112×130.25×(4.8-7.5÷3)

题目详情
下面各题怎样简便就怎样算.
87×
3
86
5
17
÷9+
1
9
×
12
17
2
15
÷[1-(
1
5
+
1
3
)]
5.37-1.47-2.53
15
7
+
11
12
+
6
7
+
1
12
×13
0.25×(4.8-7.5÷3)
▼优质解答
答案和解析
(1)87×
3
86

=86×
3
86
+1×
3
86

=3+
3
86

=3
3
86


(2)
5
17
÷9+
1
9
×
12
17

=(
5
17
+
12
17
)×
1
9

=1×
1
9

=
1
9


(3)
2
15
÷[1-(
1
5
+
1
3
)]
=
2
15
÷[1-
8
15
]
=
2
15
÷
7
15

=
2
7


(4)5.37-1.47-2.53
=5.37-(1.47+2.53)
=5.37-4
=1.37;

(5)
15
7
+
11
12
+
6
7
+
1
12
×13
=(
15
7
+
6
7
)+(
11
12
+
1
12
×13)
=3+2
=5;

(6)0.25×(4.8-7.5÷3)
=0.25×(4.8-2.5)
=0.25×2.3
=0.575.