题目内容
计算下面各题.(怎样算简便就怎样算)
(1)36×
| (2)
| (3)
| ||||||||||||||||||
(4)4.2÷1.5-0.36 | (5)(
| (6)18÷[
|
考点:分数的四则混合运算
专题:运算顺序及法则
分析:(1)(3)利用乘法分配律简算;
(2)利用加法交换律与减法的性质简算;
(4)先算除法,再算减法;
(5)先算加法,再算除法,最后算减法;
(6)先算减法,再算加法,最后算除法.
(2)利用加法交换律与减法的性质简算;
(4)先算除法,再算减法;
(5)先算加法,再算除法,最后算减法;
(6)先算减法,再算加法,最后算除法.
解答:
解:(1)36×
-
=(36-1)×
=35×
=18;
(2)
-
-
+
=(
+
)-(
+
)
=2-1
=1;
(3)
÷6+
×
=
×
+
×
=(
+
)×
=
×
=
;
(4)4.2÷1.5-0.36
=2.8-0.36
=2.44;
(5)(
+
)÷
-
=
×
-
=
-
=
;
(6)18÷[
+(
-
)]
=18÷[
+
]
=18×
=16.
18 |
35 |
18 |
35 |
=(36-1)×
18 |
35 |
=35×
18 |
35 |
=18;
(2)
11 |
10 |
1 |
4 |
3 |
4 |
9 |
10 |
=(
11 |
10 |
9 |
10 |
1 |
4 |
3 |
4 |
=2-1
=1;
(3)
9 |
20 |
1 |
20 |
1 |
6 |
=
9 |
20 |
1 |
6 |
1 |
20 |
1 |
6 |
=(
9 |
20 |
1 |
20 |
1 |
6 |
=
1 |
2 |
1 |
6 |
=
1 |
12 |
(4)4.2÷1.5-0.36
=2.8-0.36
=2.44;
(5)(
1 |
2 |
1 |
3 |
3 |
5 |
17 |
18 |
=
5 |
6 |
5 |
3 |
17 |
18 |
=
25 |
18 |
17 |
18 |
=
4 |
9 |
(6)18÷[
5 |
6 |
5 |
8 |
1 |
3 |
=18÷[
5 |
6 |
7 |
24 |
=18×
8 |
9 |
=16.
点评:混合运算的关键是抓住运算顺序,正确运用运算定律简算.
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