题目内容
计算下面各题,能简算的就简算.
|
1-
|
| ||||||||||||||||||||||
|
3-
|
分析:(1)(3)运用乘法分配律简算;
(2)先算除法,再从左到右计算减法;
(4)先算小括号里面的加法,再算括号外的乘法,最后算括号外的加法;
(5)先算乘法,再根据减法的性质简算.
(2)先算除法,再从左到右计算减法;
(4)先算小括号里面的加法,再算括号外的乘法,最后算括号外的加法;
(5)先算乘法,再根据减法的性质简算.
解答:解:(1)
×
+
×
,
=
×(
+
),
=
×1,
=
;
(2)1-
÷
-
,
=1-
-
,
=
-
,
=
;
(3)
×
+
×
,
=
×(
+
),
=
×1,
=
;
(4)
×(
+
)+
,
=
×
+
,
=
+
,
=4;
(5)3-
×
-
,
=3-
-
,
=3-(
+
),
=3-1,
=2.
4 |
9 |
5 |
6 |
4 |
9 |
1 |
6 |
=
4 |
9 |
5 |
6 |
1 |
6 |
=
4 |
9 |
=
4 |
9 |
(2)1-
7 |
36 |
5 |
18 |
5 |
18 |
=1-
7 |
10 |
5 |
18 |
=
3 |
10 |
5 |
18 |
=
1 |
45 |
(3)
3 |
8 |
3 |
5 |
3 |
8 |
2 |
5 |
=
3 |
8 |
3 |
5 |
2 |
5 |
=
3 |
8 |
=
3 |
8 |
(4)
12 |
5 |
5 |
6 |
3 |
4 |
1 |
5 |
=
12 |
5 |
19 |
12 |
1 |
5 |
=
19 |
5 |
1 |
5 |
=4;
(5)3-
3 |
2 |
10 |
21 |
2 |
7 |
=3-
5 |
7 |
2 |
7 |
=3-(
5 |
7 |
2 |
7 |
=3-1,
=2.
点评:本题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.
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