题目内容
用简便方法计算下列各题.
(
|
|
|
分析:(1)(3)运用乘法分配律简算;
(2)先通分,运用加法结合律简算.
(2)先通分,运用加法结合律简算.
解答:解:(1)(
+
)×56,
=
×56+
×56,
=16+21,
=37;
(2)
+
+
+
,
=(
+
)+(
+
),
=1+
,
=1
;
(3)
×
+
×
,
=(
+
)×
,
=1×
,
=
.
2 |
7 |
3 |
8 |
=
2 |
7 |
3 |
8 |
=16+21,
=37;
(2)
5 |
8 |
3 |
8 |
3 |
8 |
1 |
4 |
=(
5 |
8 |
3 |
8 |
3 |
8 |
2 |
8 |
=1+
5 |
8 |
=1
5 |
8 |
(3)
4 |
7 |
5 |
9 |
3 |
7 |
5 |
9 |
=(
4 |
7 |
3 |
7 |
5 |
9 |
=1×
5 |
9 |
=
5 |
9 |
点评:完成本题要注意分析式中数据,运用合适的简便方法计算.
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