题目内容
混合运算.
0.21÷[1-(4-3.25)]
(580-3660÷12)×5
×(
+
÷
)
[
-(
+
)]÷
.
0.21÷[1-(4-3.25)]
(580-3660÷12)×5
3 |
5 |
1 |
7 |
8 |
21 |
2 |
3 |
[
17 |
18 |
4 |
9 |
1 |
3 |
1 |
6 |
分析:(1)按运算顺序进行计算,先算小括号内的,再算中括号内的,最后算括号外的;
(2)按运算顺序进行计算,先算括号内的除法,再算括号内的减法,最后算括号外的乘法;
(3)按运算顺序进行计算,先算括号内的除法,再算括号内的加法,最后算括号外的乘法.
(4)按运算顺序进行计算,先算小括号内的,即(
+
),注意通分,再算中括号内的减法,最后算括号外的除法.
(2)按运算顺序进行计算,先算括号内的除法,再算括号内的减法,最后算括号外的乘法;
(3)按运算顺序进行计算,先算括号内的除法,再算括号内的加法,最后算括号外的乘法.
(4)按运算顺序进行计算,先算小括号内的,即(
4 |
9 |
1 |
3 |
解答:解:(1)0.21÷[1-(4-3.25)],
=0.21÷[1-0.75],
=0.21÷0.25,
=0.84;
(2)(580-3660÷12)×5,
=(580-305)×5,
=275×5,
=1375;
(3)
×(
+
÷
),
=
×(
+
×
),
=
×(
+
),
=
×
,
=
;
(4)[
-(
+
)]÷
,
=[
-(
+
)]×6,
=[
-
]×6,
=[
-
]×6,
=
×6,
=1.
=0.21÷[1-0.75],
=0.21÷0.25,
=0.84;
(2)(580-3660÷12)×5,
=(580-305)×5,
=275×5,
=1375;
(3)
3 |
5 |
1 |
7 |
8 |
21 |
2 |
3 |
=
3 |
5 |
1 |
7 |
8 |
21 |
3 |
2 |
=
3 |
5 |
1 |
7 |
4 |
7 |
=
3 |
5 |
5 |
7 |
=
3 |
7 |
(4)[
17 |
18 |
4 |
9 |
1 |
3 |
1 |
6 |
=[
17 |
18 |
4 |
9 |
3 |
9 |
=[
17 |
18 |
7 |
9 |
=[
17 |
18 |
14 |
18 |
=
1 |
6 |
=1.
点评:此题重点考查学生对四则混合运算顺序的掌握情况以及计算能力.
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