题目内容
(2011?常宁市)
脱式计算.(能简算的要简算) 0.25×12.5×8 |
6.4×
|
[1-(
|
分析:(1)运用乘法结合律简算;
(2)运用乘法分配律简算;
(3)先算小括号内的,再算中括号内的,最后算括号外的.
(2)运用乘法分配律简算;
(3)先算小括号内的,再算中括号内的,最后算括号外的.
解答:解:(1)0.25×12.5×8,
=0.25×(12.5×8),
=0.25×100,
=25;
(2)6.4×
+
×3.6,
=(6.4+3.6)×
,
=10×
,
=4;
(3)[1-(
-
)]×
,
=[1-
]×
,
=
×
,
=
.
=0.25×(12.5×8),
=0.25×100,
=25;
(2)6.4×
2 |
5 |
2 |
5 |
=(6.4+3.6)×
2 |
5 |
=10×
2 |
5 |
=4;
(3)[1-(
1 |
3 |
1 |
5 |
15 |
26 |
=[1-
2 |
15 |
15 |
26 |
=
13 |
15 |
15 |
26 |
=
1 |
2 |
点评:完成此题,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.
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