| 简便计算 (1)35×(- ) | (2)12×(0.25- ) |
| (3)28x0.36+280×0.064 | (4)13×0.25+5÷4. |
),=35×1-35×
,=35-(34+1)×
,=35-3-
,=32-
,=31
;(2)12×(0.25-
),=12×(
-
),=12×
-12×
,=3-2,
=1;
(3)28×0.36+280×0.064,
=280×0.036+280×0.064,
=280×(0.036+0.064),
=280×0.1,
=28;
(4)13×0.25+5÷4,
=13×
+5×
,=(13+5)×
,=18×
,=4.5.
分析:(1)运用乘法分配律简算;
(2)把0.25化为分数,运用乘法分配律简算;
(3)把原式变为280×0.036+280×0.064,运用乘法分配律简算;
(4)把0.25化为分数,把除法转化为乘法,运用乘法分配律简算.
点评:完成此题,注意分析式中数据,灵活运用运算定律,进行简便计算.