题目内容
(39+
|
(
|
|
分析:(1)运用乘法分配律简算;
(2)先算小括号里面的减法,再算括号外的除法;
(3)先把除法变成乘法,再运用乘法分配律简算.
(2)先算小括号里面的减法,再算括号外的除法;
(3)先把除法变成乘法,再运用乘法分配律简算.
解答:解:(1)(39+
)×
,
=39×
+
×
,
=3+
,
=3
;
(2)(
-
)÷
,
=
×
,
=
;
(3)
÷7+
×
,
=
×
+
×
,
=(
+
)×
,
=1×
,
=
.
| 13 |
| 14 |
| 1 |
| 13 |
=39×
| 1 |
| 13 |
| 13 |
| 14 |
| 1 |
| 13 |
=3+
| 1 |
| 14 |
=3
| 1 |
| 14 |
(2)(
| 3 |
| 4 |
| 1 |
| 8 |
| 5 |
| 12 |
=
| 5 |
| 8 |
| 12 |
| 5 |
=
| 3 |
| 2 |
(3)
| 8 |
| 13 |
| 1 |
| 7 |
| 5 |
| 13 |
=
| 8 |
| 13 |
| 1 |
| 7 |
| 1 |
| 7 |
| 5 |
| 13 |
=(
| 8 |
| 13 |
| 5 |
| 13 |
| 1 |
| 7 |
=1×
| 1 |
| 7 |
=
| 1 |
| 7 |
点评:此题主要考查分数的四则混合运算的运算顺序,以及应用运算定律进行简便计算的能力.
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