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×
−26)×4 13
8 11
(5)
×7 8
+12 13
÷13. 7 8
答
(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×
−26)×4 13
8 11
=(48-26)×
,8 11
=22×
,8 11
=16;
(5)
×7 8
+12 13
÷137 8
=
×7 8
+12 13
×7 8
,1 13
=
×(7 8
+12 13
),1 13
=
.7 8