题目内容
用递等式计算下面各题.
15.2×
|
| 5-
| (
| ||||||||||||||||||||
| 4÷
| 9×
|
|
考点:整数、分数、小数、百分数四则混合运算,运算定律与简便运算
专题:运算顺序及法则,运算定律及简算
分析:(1)运用乘法分配律简算.
(2)(4)先算括号内的,再算括号外的.
(3)运用减法的性质简算.
(5)先算除法,再算减法.
(6)把除法变为除法,约分计算.
(7)先算乘除,再算加法.
(8)先算除法,再算加法.
(2)(4)先算括号内的,再算括号外的.
(3)运用减法的性质简算.
(5)先算除法,再算减法.
(6)把除法变为除法,约分计算.
(7)先算乘除,再算加法.
(8)先算除法,再算加法.
解答:
解:(1)15.2×
+15.2×
=15.2×(
+
)
=15.2×1
=15.2
(2)
×(
-
)
=
×
=
(3)5-
-
=5-(
+
)
=5-1
=4
(4)(
-
)÷
=
×
=
(5)
÷3-
=
×
-
=
-
=
(6)4÷
÷
=4×
×
=
(7)9×
+
÷9
=9×
+
×
=9×
+
=
+
=
3 |
8 |
5 |
8 |
=15.2×(
3 |
8 |
5 |
8 |
=15.2×1
=15.2
(2)
3 |
10 |
5 |
7 |
10 |
21 |
=
3 |
10 |
5 |
21 |
=
1 |
14 |
(3)5-
3 |
7 |
4 |
7 |
=5-(
3 |
7 |
4 |
7 |
=5-1
=4
(4)(
1 |
2 |
1 |
3 |
3 |
8 |
=
1 |
6 |
8 |
3 |
=
4 |
9 |
(5)
5 |
7 |
2 |
21 |
=
5 |
7 |
1 |
3 |
2 |
21 |
=
5 |
21 |
2 |
21 |
=
1 |
7 |
(6)4÷
2 |
3 |
9 |
20 |
=4×
3 |
2 |
20 |
9 |
=
40 |
3 |
(7)9×
9 |
13 |
9 |
13 |
=9×
9 |
13 |
9 |
13 |
1 |
9 |
=9×
9 |
13 |
1 |
13 |
=
81 |
13 |
1 |
13 |
=
82 |
13 |
点评:此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简便计算.
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