题目内容
| 用自己喜欢的方法计算: 12-
|
76×
|
(
|
|
分析:(1)把除法改为乘法,运用加法结合律简算;
(2)把76看作77-1,运用乘法分配律简算;
(3)根据数字特点,运用乘法分配律简算;
(4)把除法改为乘法,运用乘法分配律简算.
(2)把76看作77-1,运用乘法分配律简算;
(3)根据数字特点,运用乘法分配律简算;
(4)把除法改为乘法,运用乘法分配律简算.
解答:解:(1)12-
+
÷
,
=12-
+
×5,
=12+(
-
),
=12+
,
=12
;
(2)76×
,
=(77-1)×
,
=77×
-
,
=76-
,
=75
;
(3)(
+
)×5×7,
=
×5×7+
×5×7,
=14+30,
=44;
(4)
÷7+
×
,
=
×
+
×
,
=(
+
)×
,
=1×
,
=
.
| 2 |
| 7 |
| 1 |
| 7 |
| 1 |
| 5 |
=12-
| 2 |
| 7 |
| 1 |
| 7 |
=12+(
| 5 |
| 7 |
| 2 |
| 7 |
=12+
| 3 |
| 7 |
=12
| 3 |
| 7 |
(2)76×
| 76 |
| 77 |
=(77-1)×
| 76 |
| 77 |
=77×
| 76 |
| 77 |
| 76 |
| 77 |
=76-
| 76 |
| 77 |
=75
| 1 |
| 77 |
(3)(
| 2 |
| 5 |
| 6 |
| 7 |
=
| 2 |
| 5 |
| 6 |
| 7 |
=14+30,
=44;
(4)
| 5 |
| 12 |
| 7 |
| 12 |
| 1 |
| 7 |
=
| 5 |
| 12 |
| 1 |
| 7 |
| 7 |
| 12 |
| 1 |
| 7 |
=(
| 5 |
| 12 |
| 7 |
| 12 |
| 1 |
| 7 |
=1×
| 1 |
| 7 |
=
| 1 |
| 7 |
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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