题目内容
用简便方法计算.
7-
-
÷
×
+
×
.
7-
| 3 |
| 7 |
| 1 |
| 7 |
| 1 |
| 4 |
| 4 |
| 9 |
| 11 |
| 5 |
| 1 |
| 9 |
| 11 |
| 5 |
分析:算式(1)可将式中除法算式算出结果后,根据一个数减两个数,等于用这个数减去这两个数的和的减法性质进行计算;
算式(2)可根据乘法分配律进行计算.
算式(2)可根据乘法分配律进行计算.
解答:解:(1)7-
-
÷
=7-
-
,
=7-(
+
),
=7-1,
=6;
(2)
×
+
×
=(
+
)×
,
=
×
,
=
.
| 3 |
| 7 |
| 1 |
| 7 |
| 1 |
| 4 |
=7-
| 3 |
| 7 |
| 4 |
| 7 |
=7-(
| 3 |
| 7 |
| 4 |
| 7 |
=7-1,
=6;
(2)
| 4 |
| 9 |
| 11 |
| 5 |
| 1 |
| 9 |
| 11 |
| 5 |
=(
| 4 |
| 9 |
| 1 |
| 9 |
| 11 |
| 5 |
=
| 5 |
| 9 |
| 11 |
| 5 |
=
| 11 |
| 9 |
点评:本题考查的知识点为:减法的性质、乘法分配律.
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