题目内容
计算下面各题,能用简便算法的就用简便算法.
(1)
|
(2)
| ||||||||||||||
(3)(
|
(4)
|
分析:(1)根据乘法分配律进行简算;
(2)先算除法,再根据连减的性质进行简算;
(3)先算小括号里面的减法,再算除法;
(4)先算小括号里面的加法,再算中括号里面的乘法,最后算除法.
(2)先算除法,再根据连减的性质进行简算;
(3)先算小括号里面的减法,再算除法;
(4)先算小括号里面的加法,再算中括号里面的乘法,最后算除法.
解答:解:(1)
÷9+
×
,
=
×
+
×
,
=(
+
)×
,
=1×
,
=
;
(2)
-
-
÷
,
=
-
-
,
=
-(
+
),
=
-1,
=
;
(3)(
-
)÷
,
=
÷
,
=
;
(4)
÷[(
+
)×
],
=
÷[
×
],
=
÷
,
=
.
7 |
10 |
3 |
10 |
1 |
9 |
=
7 |
10 |
1 |
9 |
3 |
10 |
1 |
9 |
=(
7 |
10 |
3 |
10 |
1 |
9 |
=1×
1 |
9 |
=
1 |
9 |
(2)
7 |
5 |
5 |
8 |
9 |
16 |
3 |
2 |
=
7 |
5 |
5 |
8 |
3 |
8 |
=
7 |
5 |
5 |
8 |
3 |
8 |
=
7 |
5 |
=
2 |
5 |
(3)(
3 |
4 |
1 |
8 |
5 |
12 |
=
5 |
8 |
5 |
12 |
=
3 |
2 |
(4)
4 |
5 |
1 |
2 |
2 |
5 |
2 |
3 |
=
4 |
5 |
9 |
10 |
2 |
3 |
=
4 |
5 |
3 |
5 |
=
4 |
3 |
点评:四则运算,先弄清运算顺序,然后再进一步计算即可,能简算的要简算.
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