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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