题目内容
脱式计算:
×9-6÷
=
[1-(
-
)]×
=
×8+8×
=
| 3 |
| 7 |
| 7 |
| 3 |
[1-(
| 1 |
| 2 |
| 1 |
| 4 |
| 2 |
| 3 |
| 5 |
| 4 |
| 1 |
| 4 |
分析:(1)除法改为乘后,利用乘法分配律简算;
(2)先算小括号里面的减法,再算中括号里面的减法,最后算括号外面的乘法;
(3)利用乘法分配律简算.
(2)先算小括号里面的减法,再算中括号里面的减法,最后算括号外面的乘法;
(3)利用乘法分配律简算.
解答:解:(1)
×9-6÷
,
=
×9-6×
,
=
×(9-6),
=
;
(2)[1-(
-
)]×
,
=[1-
]×
,
=
×
,
=
;
(3)
×8+8×
,
=8×(
+
),
=8×
,
=12.
| 3 |
| 7 |
| 7 |
| 3 |
=
| 3 |
| 7 |
| 3 |
| 7 |
=
| 3 |
| 7 |
=
| 9 |
| 7 |
(2)[1-(
| 1 |
| 2 |
| 1 |
| 4 |
| 2 |
| 3 |
=[1-
| 1 |
| 4 |
| 2 |
| 3 |
=
| 3 |
| 4 |
| 2 |
| 3 |
=
| 1 |
| 2 |
(3)
| 5 |
| 4 |
| 1 |
| 4 |
=8×(
| 5 |
| 4 |
| 1 |
| 4 |
=8×
| 3 |
| 2 |
=12.
点评:计算注意抓住运算顺序,结合运算定律,灵活计算.
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