题目内容
脱式计算 15-2×
|
|
| ||||||||||||||
(125+
|
| 12×(
|
考点:分数的四则混合运算
专题:运算顺序及法则
分析:(1)先算乘法,再算减法;
(2)把除以
化成乘以
,再约分计算即可;
(3)先算小括号里的减法,再算括号外的除法;
(4)运用乘法的分配律进行简算;
(5)运用乘法的分配律进行简算;
(6)运用乘法的分配律进行简算.
(2)把除以
21 |
36 |
36 |
21 |
(3)先算小括号里的减法,再算括号外的除法;
(4)运用乘法的分配律进行简算;
(5)运用乘法的分配律进行简算;
(6)运用乘法的分配律进行简算.
解答:
解:(1)15-2×
=15-
=14
;
(2)
×
÷
=
×
×
=
=
;
(3)
÷(
-
)
=
÷
=
;
(4)(125+
)×8
=125×8+
×8
=1000+
=1000
;
(5)
×24+24×
=(
+
)×24
=1×24
=24;
(6)12×(
+
-
)
=12×
+12×
-12×
=3+2-4
=5-4
=1.
6 |
13 |
=15-
12 |
13 |
=14
1 |
13 |
(2)
7 |
24 |
3 |
5 |
21 |
36 |
=
7 |
24 |
3 |
5 |
36 |
21 |
=
7×3×36 |
24×5×21 |
=
3 |
10 |
(3)
15 |
36 |
1 |
3 |
1 |
18 |
=
15 |
36 |
5 |
18 |
=
3 |
2 |
(4)(125+
1 |
32 |
=125×8+
1 |
32 |
=1000+
1 |
4 |
=1000
1 |
4 |
(5)
1 |
9 |
8 |
9 |
=(
1 |
9 |
8 |
9 |
=1×24
=24;
(6)12×(
1 |
4 |
1 |
6 |
1 |
3 |
=12×
1 |
4 |
1 |
6 |
1 |
3 |
=3+2-4
=5-4
=1.
点评:此题考查了四则混合运算,注意运算顺序,运用运算定律灵活简算.
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