题目内容
(2008?纳溪区模拟)下面各题怎样简便就怎样算.
(1)
÷
÷
(2)(
+
)×
(3)13.2÷(3.2×3-0.8)
(4)
÷[(
-
)×12].
(1)
2 |
5 |
3 |
4 |
1 |
15 |
(2)(
3 |
5 |
1 |
6 |
3 |
7 |
(3)13.2÷(3.2×3-0.8)
(4)
7 |
9 |
5 |
8 |
1 |
4 |
分析:(1)把除法改为乘法,约分计算即可;
(2)(3)题,按运算顺序计算,先算括号内的,再算括号外的;
(4)按运算顺序计算,先算小括号内的,再算中括号内的,最后算括号外的.
(2)(3)题,按运算顺序计算,先算括号内的,再算括号外的;
(4)按运算顺序计算,先算小括号内的,再算中括号内的,最后算括号外的.
解答:解:(1)
÷
÷
,
=
×
×15,
=8;
(2)(
+
)×
,
=(
+
)×
,
=
×
,
=
;
(3)13.2÷(3.2×3-0.8),
=13.2÷(9.6-0.8),
=13.2÷8.8,
=1.5;
(4)
÷[(
-
)×12],
=
÷[
×12],
=
÷
,
=
×
,
=
.
2 |
5 |
3 |
4 |
1 |
15 |
=
2 |
5 |
4 |
3 |
=8;
(2)(
3 |
5 |
1 |
6 |
3 |
7 |
=(
18 |
30 |
5 |
30 |
3 |
7 |
=
23 |
30 |
3 |
7 |
=
23 |
70 |
(3)13.2÷(3.2×3-0.8),
=13.2÷(9.6-0.8),
=13.2÷8.8,
=1.5;
(4)
7 |
9 |
5 |
8 |
1 |
4 |
=
7 |
9 |
3 |
8 |
=
7 |
9 |
9 |
2 |
=
7 |
9 |
2 |
9 |
=
14 |
81 |
点评:此题重点考查学生对四则混合运算顺序的掌握情况;注意能约分的要先约分.
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