| 脱式计算. 2004×8.1+1.9×2004 | -( + × )×![]() | (1- )÷( + ) |
| 4.38×0.75+3.62×0.75 | 12 ×11-12.5 | 35÷[( - )×3]. |
=(8.1+1.9)×2004,
=10×2004,
=20040;
(2)
-(
+
×
)×
=
-(
+
)×
,=
-
×
,=

,=0;
(3)(1-
)÷(
+
)=
÷
,=
;(4)4.38×0.75+3.62×0.75
=(4.38+3.62)×0.75,
=8×0.75,
=6;
(5)12
×11-12.5=12.5×11-12.5,
=(11-1)×12.5,
=10×12.5,
=125;
(6)35÷[(
-
)×3].=35÷[
×3],=35÷1,
=35.
分析:(1)(4)(5)可根据乘法分配律计算;
(2)(3)(6)根据四则混合运算的运算顺序计算即可:先算乘除,再算加减,有括号的要先算括号里面的.
点评:完成脱式计算时要注意计算过程的完整性,中间不要有太大跳跃.