题目内容
| 用简便方法计算. (
|
|
|
|
分析:(1)(2)直接约分计算即可;
(3)(4)利用乘法分配律简算.
(3)(4)利用乘法分配律简算.
解答:解:(1)(
×
)×
=
×
=
;
(2)
×
×
=
;
(3)
×
+
×
=(
+
)×
=1×
=
;
(4)
×28-
=
×(56-7)
=
×49
=
.
| 1 |
| 3 |
| 2 |
| 5 |
| 15 |
| 16 |
=
| 2 |
| 15 |
| 15 |
| 16 |
=
| 1 |
| 8 |
(2)
| 5 |
| 9 |
| 6 |
| 5 |
| 3 |
| 4 |
=
| 1 |
| 2 |
(3)
| 3 |
| 8 |
| 4 |
| 7 |
| 5 |
| 8 |
| 4 |
| 7 |
=(
| 3 |
| 8 |
| 5 |
| 8 |
| 4 |
| 7 |
=1×
| 4 |
| 7 |
=
| 4 |
| 7 |
(4)
| 2 |
| 27 |
| 7 |
| 27 |
=
| 1 |
| 27 |
=
| 1 |
| 27 |
=
| 49 |
| 27 |
点评:此题考查分数四则混合运算,注意运算顺序,根据数字特点灵活利用运算定律简算.
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