用递等式计算,能简算的简算 (1)85×54÷18+745 (2)3.4÷[(1.25+0.45)×23] (3)35×(1−3/7)÷5/12 (4)(156×4/13−26)×8/11 (5)7/8×12/13+7/8÷13.

问题描述:

用递等式计算,能简算的简算
(1)85×54÷18+745
(2)3.4÷[(1.25+0.45)×23]
(3)35×(1−

3
7
5
12

(4)(156×
4
13
−26)×
8
11

(5)
7
8
×
12
13
+
7
8
÷13


(1)85×54÷18+745
=85×(54÷18)+745,
=85×3+745,
=255+745,
=1000;
(2)3.4÷[(1.25+0.45)×23]
=3.4÷(1.25+0.45)÷23,
=3.4÷1.7÷23,
=2÷23,
=

2
23

(3)35×(1−
3
7
5
12

=35×
4
7
÷
5
12

=20÷
5
12

=48;
(4)(156×
4
13
−26)×
8
11

=(48-26)×
8
11

=22×
8
11

=16;
(5)
7
8
×
12
13
+
7
8
÷13

=
7
8
×
12
13
+
7
8
×
1
13

=
7
8
×
12
13
+
1
13
),
=
7
8