题目内容
| 脱式计算. (
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[
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分析:(1)先算小括号里面的减法,再算括号外的乘法;
(2)先算小括号里面的除法,再算括号外的除法;
(3)先算小括号里面的减法,再算中括号里面的乘法,最后算括号外的除法;
(4)先算除法,再算加法;
(5)先算小括号里面的乘法,再把除法变成乘法,运用乘法交换律简算;
(6)先算小括号里面的减法,再算中括号里里面的减法,最后算括号外的除法.
(2)先算小括号里面的除法,再算括号外的除法;
(3)先算小括号里面的减法,再算中括号里面的乘法,最后算括号外的除法;
(4)先算除法,再算加法;
(5)先算小括号里面的乘法,再把除法变成乘法,运用乘法交换律简算;
(6)先算小括号里面的减法,再算中括号里里面的减法,最后算括号外的除法.
解答:解:(1)(
-
)×
,
=
×
,
=
;
(2)
÷(
÷
),
=
÷
,
=2;
(3)
÷[(
-
)×
],
=
÷[
×
],
=
÷
,
=1;
(4)
+
÷
,
=
+
,
=
;
(5)
×(
+
)÷
,
=
×
×
,
=(
×
)×
,
=1×
,
=
;
(6)[
-(
-
)]÷
,
=[
-
]÷
,
=
÷
,
=
.
| 3 |
| 4 |
| 5 |
| 8 |
| 4 |
| 15 |
=
| 1 |
| 8 |
| 4 |
| 15 |
=
| 1 |
| 30 |
(2)
| 3 |
| 5 |
| 4 |
| 15 |
| 8 |
| 9 |
=
| 3 |
| 5 |
| 3 |
| 10 |
=2;
(3)
| 1 |
| 8 |
| 3 |
| 8 |
| 1 |
| 6 |
| 3 |
| 5 |
=
| 1 |
| 8 |
| 5 |
| 24 |
| 3 |
| 5 |
=
| 1 |
| 8 |
| 1 |
| 8 |
=1;
(4)
| 5 |
| 6 |
| 2 |
| 9 |
| 2 |
| 3 |
=
| 5 |
| 6 |
| 1 |
| 3 |
=
| 7 |
| 6 |
(5)
| 15 |
| 16 |
| 1 |
| 6 |
| 1 |
| 4 |
| 15 |
| 16 |
=
| 15 |
| 16 |
| 5 |
| 12 |
| 16 |
| 15 |
=(
| 15 |
| 16 |
| 16 |
| 15 |
| 5 |
| 12 |
=1×
| 5 |
| 12 |
=
| 5 |
| 12 |
(6)[
| 2 |
| 5 |
| 1 |
| 2 |
| 2 |
| 5 |
| 3 |
| 2 |
=[
| 2 |
| 5 |
| 1 |
| 10 |
| 3 |
| 2 |
=
| 3 |
| 10 |
| 3 |
| 2 |
=
| 1 |
| 5 |
点评:1、如果是同一级运算,一般按从左往右依次进行计算;2、如果既有加减、又有乘除法,先算乘除法、再算加减;3、如果有括号,先算括号里面的.
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