题目内容
(2008?门头沟区)用简便方法计算:
(
+
+
)×72;
÷13+
×
.
(
| 5 |
| 12 |
| 1 |
| 9 |
| 3 |
| 8 |
| 8 |
| 17 |
| 1 |
| 13 |
| 9 |
| 17 |
分析:通过分析式中数字的规律,发现本题中的两个算式都可以根据乘法分配律进行简便计算.
解答:解:(
+
+
)×72,
=
×72+
×72+
×72;
=30+8+27,
=65;
÷13+
×
,
=
×
+
×
,
=(
+
)×
,
=1×
,
=
.
| 5 |
| 12 |
| 1 |
| 9 |
| 3 |
| 8 |
=
| 5 |
| 12 |
| 1 |
| 9 |
| 3 |
| 8 |
=30+8+27,
=65;
| 8 |
| 17 |
| 1 |
| 13 |
| 9 |
| 17 |
=
| 8 |
| 17 |
| 1 |
| 13 |
| 1 |
| 13 |
| 9 |
| 17 |
=(
| 8 |
| 17 |
| 9 |
| 17 |
| 1 |
| 13 |
=1×
| 1 |
| 13 |
=
| 1 |
| 13 |
点评:完成此类式中数据,根据式中数据的特点选择合适的方法进行简便计算.
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