题目内容
计算下面各题,能简便的要简便计算.
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分析:根据分数四则混合运算的顺序和计算法则进行计算,其中有两道题可以利用乘法分配律进行简算.
解答:解:(1)
×2+
÷2
=0.75×2+0.4÷2
=1.5+0.2
=1.7;
(2)
÷
+
÷
=(
+
)×
=1×
=1
;
(3)
-
×
+
=
-
+
=
+
=1
;
(4)
×
+
×
=
×(
+
)
=
×1
=
;
(5)(
×
-
)÷
=(
-
)÷
=
×
;
(6)
÷[1-(
-
)]
÷[1-
]
=
÷
=1;
| 3 |
| 4 |
| 2 |
| 5 |
=0.75×2+0.4÷2
=1.5+0.2
=1.7;
(2)
| 1 |
| 3 |
| 5 |
| 8 |
| 2 |
| 3 |
| 5 |
| 8 |
=(
| 1 |
| 3 |
| 2 |
| 3 |
| 8 |
| 5 |
=1×
| 8 |
| 5 |
=1
| 3 |
| 5 |
(3)
| 11 |
| 7 |
| 8 |
| 7 |
| 5 |
| 8 |
| 5 |
| 14 |
=
| 11 |
| 7 |
| 5 |
| 7 |
| 5 |
| 14 |
=
| 6 |
| 7 |
| 5 |
| 14 |
=1
| 3 |
| 14 |
(4)
| 7 |
| 12 |
| 3 |
| 5 |
| 7 |
| 12 |
| 2 |
| 5 |
=
| 7 |
| 12 |
| 3 |
| 5 |
| 2 |
| 5 |
=
| 7 |
| 12 |
=
| 7 |
| 12 |
(5)(
| 1 |
| 3 |
| 6 |
| 7 |
| 1 |
| 14 |
| 14 |
| 15 |
=(
| 2 |
| 7 |
| 1 |
| 14 |
| 14 |
| 15 |
=
| 3 |
| 14 |
| 15 |
| 14 |
| 45 |
| 196 |
(6)
| 5 |
| 6 |
| 2 |
| 3 |
| 1 |
| 2 |
| 5 |
| 6 |
| 1 |
| 6 |
=
| 5 |
| 6 |
| 5 |
| 6 |
=1;
点评:此题主要考查分数四则混合运算的计算能力,计算时要认真分析能用简便方法的就用简便方法计算.
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