问题
解答题
用简便方法计算. (1)56×
(2)3.3×
|
答案
(1)56×
,56 57
=(57-1)×
,56 57
=57×
-1×56 57 56 57
=56-
,56 57
=55
;1 57
(2)3.3×
+0.75×5.7+75%,3 4
=(3.3+5.7+1)×0.75,
=10×0.75,
=7.5.
用简便方法计算. (1)56×
(2)3.3×
|
(1)56×
,56 57
=(57-1)×
,56 57
=57×
-1×56 57 56 57
=56-
,56 57
=55
;1 57
(2)3.3×
+0.75×5.7+75%,3 4
=(3.3+5.7+1)×0.75,
=10×0.75,
=7.5.