用你喜欢的方法计算下面各题 ÷〔 ×(1- )〕 | ( - )×![]() |
| (20-1.25×0.8)÷0.19 | 6.88×7.8+3.2×6.88-6.88 |
5.58- +5.42-![]() | 325×0.36+6.75×36. |
÷[
×(1-
)],=
÷[
×
],=
÷
,=
×6,=
;(2)(
-
)×
,=
×
-
×
,=
-
,=
;(3)(20-1.25×0.8)÷0.19,
=(20-1)÷0.19,
=19÷0.19,
=100;
(4)6.88×7.8+3.2×6.88-6.88,
=6.88×(7.8+3.2-1),
=6.88×10,
=68.8;
(5)5.58-
+5.42-
,=(5.58+5.42)-(
+
),=11-1,
=10;
(6)325×0.36+6.75×36,
=3.25×36+6.75×36,
=(3.25+6.75)×36,
=10×36,
=360.
分析:(1)先算小括号内的,再算中括号内的,最后算括号外的;
(2)(4)运用乘法分配律简算;
(3)先算括号内的乘法,再算括号内的减法,最后算括号外的除法;
(5)运用加法交换律与结合律简算;
(6)根据数字特点,把原式变为3.25×36+6.75×36,运用乘法分配律简算.
点评:此题主要考查分数、小数的四则混合运算的运算顺序和应用运算定律进行简便计算.