题目内容
简便计算
17×(
+
)×18-40
1.25×3.2×0.25
7
-(3.875-2.64)
17×(
| 3 |
| 17 |
| 7 |
| 18 |
1.25×3.2×0.25
7
| 7 |
| 8 |
分析:(1)17×(
+
)×18-40,运用乘法分配律进行简算;
(2)1.25×3.2×0.25,把3.2拆分为:0.8×4,再运用乘法结合律进行简算;
(3)7
-(3.875-2.64),根据减法的运算性质进行简算.
| 3 |
| 17 |
| 7 |
| 18 |
(2)1.25×3.2×0.25,把3.2拆分为:0.8×4,再运用乘法结合律进行简算;
(3)7
| 7 |
| 8 |
解答:解:(1)17×(
+
)×18-40,
=17×
×18+17×
×18-40,
=54+119-40,
=173-40,
=133;
(2)1.25×3.2×0.25,
=(1.25×0.8)×(4×0.25),
=1×1,
=1;
(3)7
-(3.875-2.64),
=7.875-3.875+2.64,
=4+2.64,
=6.64;
| 3 |
| 17 |
| 7 |
| 18 |
=17×
| 3 |
| 17 |
| 7 |
| 18 |
=54+119-40,
=173-40,
=133;
(2)1.25×3.2×0.25,
=(1.25×0.8)×(4×0.25),
=1×1,
=1;
(3)7
| 7 |
| 8 |
=7.875-3.875+2.64,
=4+2.64,
=6.64;
点评:此题考查的目的是掌握乘法的运算定律和减法的运算性质,并且能够灵活运用这些运算定律和运算性质进行简便计算.
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