题目内容
能简便计算的要简便计算.
×
+
÷
30×(
-
-
)
39×
×
×
.
| 3 |
| 5 |
| 2 |
| 11 |
| 2 |
| 11 |
| 5 |
| 2 |
30×(
| 4 |
| 5 |
| 1 |
| 3 |
| 1 |
| 15 |
39×
| 39 |
| 40 |
| 10 |
| 13 |
| 26 |
| 35 |
| 1 |
| 5 |
考点:分数的简便计算
专题:运算顺序及法则
分析:(1)运用乘法的分配律进行简算;
(2)运用乘法的分配律进行简算;
(3)把39化成40-1,再进行简算;
(4)运用乘法法的性质进行简算.
(2)运用乘法的分配律进行简算;
(3)把39化成40-1,再进行简算;
(4)运用乘法法的性质进行简算.
解答:
解:(10
×
+
÷
=
×
+
×
=
×(
+
)
=
×1
=
(2)30×(
-
-
)
=30×
-30×
-30×
=24-10-2
=12
(3)39×
=(40-1)×
=40×
-
=39-
=38
(4)
×
×
=
| 3 |
| 5 |
| 2 |
| 11 |
| 2 |
| 11 |
| 5 |
| 2 |
=
| 3 |
| 5 |
| 2 |
| 11 |
| 2 |
| 11 |
| 2 |
| 5 |
=
| 2 |
| 11 |
| 2 |
| 5 |
| 3 |
| 5 |
=
| 2 |
| 11 |
=
| 2 |
| 11 |
(2)30×(
| 4 |
| 5 |
| 1 |
| 3 |
| 1 |
| 15 |
=30×
| 4 |
| 5 |
| 1 |
| 3 |
| 1 |
| 15 |
=24-10-2
=12
(3)39×
| 39 |
| 40 |
=(40-1)×
| 39 |
| 40 |
=40×
| 39 |
| 40 |
| 39 |
| 40 |
=39-
| 39 |
| 40 |
=38
| 1 |
| 40 |
(4)
| 10 |
| 13 |
| 26 |
| 35 |
| 1 |
| 5 |
=
| 4 |
| 35 |
点评:此题考查学生灵活运用运算定律简算的能力,以及对运算顺序的考查.
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