题目内容
脱式计算.
|
| ||||||||||||||
2×[(
|
|
分析:(1)先算小括号里面的减法,再算括号外的除法,最后算括号外的乘法;
(2)先算小括号里面的减法,再算括号外的乘法,最后算括号外的除法;
(3)先算小括号里面的加法,再算中括号里面的除法,最后算括号外的乘法;
(4)先算小括号里面的加法,再算中括号里面的乘法,最后算括号外的除法.
(2)先算小括号里面的减法,再算括号外的乘法,最后算括号外的除法;
(3)先算小括号里面的加法,再算中括号里面的除法,最后算括号外的乘法;
(4)先算小括号里面的加法,再算中括号里面的乘法,最后算括号外的除法.
解答:解:(1)
÷
×(1-
),
=
÷
×
,
=
×
,
=
;
(2)
×
÷(
-
),
=
×
÷
,
=
×
,
=
;
(3)2×[(
+
)÷6],
=2×[
÷6],
=2×
,
=
;
(4)
÷[(
+
)×
],
=
÷[
×
],
=
÷
,
=
.
| 2 |
| 3 |
| 8 |
| 9 |
| 1 |
| 4 |
=
| 2 |
| 3 |
| 8 |
| 9 |
| 3 |
| 4 |
=
| 3 |
| 4 |
| 3 |
| 4 |
=
| 9 |
| 16 |
(2)
| 1 |
| 6 |
| 2 |
| 3 |
| 4 |
| 5 |
| 8 |
| 15 |
=
| 1 |
| 6 |
| 2 |
| 3 |
| 4 |
| 15 |
=
| 1 |
| 9 |
| 15 |
| 4 |
=
| 5 |
| 12 |
(3)2×[(
| 5 |
| 6 |
| 2 |
| 3 |
=2×[
| 9 |
| 6 |
=2×
| 1 |
| 4 |
=
| 1 |
| 2 |
(4)
| 7 |
| 8 |
| 1 |
| 5 |
| 2 |
| 5 |
| 1 |
| 2 |
=
| 7 |
| 8 |
| 3 |
| 5 |
| 1 |
| 2 |
=
| 7 |
| 8 |
| 3 |
| 10 |
=
| 35 |
| 12 |
点评:1.一个算式里,如果含有两级运算,要先做第二级运算,后做第一级运算.
2.一个算式里,如果有括号,要先算小括号里的,再算中括号里面的.
2.一个算式里,如果有括号,要先算小括号里的,再算中括号里面的.
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