题目内容
|
| ||||||||||||||||
(
|
[2-(
| ||||||||||||||||
(
|
| ||||||||||||||||
[
|
|
分析:(1)把除法算式化成乘法算式,再运用乘法的分配律进行简算,
(2)先算乘法,再运用加法的结合律进行简算,
(3)先算小括号里的除法,再算小括号里的减法,最后算括号外的除法,
(4)先算小括号里的加法,再算中括号里的减法,最后算括号外的乘法,
(5)运用乘法的分配律进行简算,
(6)先算乘法算式和除法算式,再算减法,
(7)先算小括号里的减法,再算中括号里的减法,最后算括号外的乘法,
(8)先算小括号里的减法,再从左向右进行计算.
(2)先算乘法,再运用加法的结合律进行简算,
(3)先算小括号里的除法,再算小括号里的减法,最后算括号外的除法,
(4)先算小括号里的加法,再算中括号里的减法,最后算括号外的乘法,
(5)运用乘法的分配律进行简算,
(6)先算乘法算式和除法算式,再算减法,
(7)先算小括号里的减法,再算中括号里的减法,最后算括号外的乘法,
(8)先算小括号里的减法,再从左向右进行计算.
解答:解:(1)
÷
+
÷
,
=
×
+
×
,
=(
+
)×
,
=1×
,
=
;
(2)
+
×
+
,
=
+
+
,
=
+(
+
),
=
+1,
=3
;
(3)(
-
÷
)÷
,
=(
-
)÷
,
=
÷
,
=
;
(4)[2-(
+
)]×
,
=[2-
]×
,
=
×
,
=
;
(5)(
-
)×21,
=
×21-
×21,
=35-6,
=29;
(6)
×15-3÷
,
=
-
,
=4.5;
(7)[
-(
-
)]×
,
=[
-
]×
,
=
×
,
=
;
(8)
×
÷(
-
),
=
×
÷
,
=
×
×
,
=
.
| 17 |
| 25 |
| 4 |
| 3 |
| 8 |
| 25 |
| 4 |
| 3 |
=
| 17 |
| 25 |
| 3 |
| 4 |
| 8 |
| 25 |
| 3 |
| 4 |
=(
| 17 |
| 25 |
| 8 |
| 25 |
| 3 |
| 4 |
=1×
| 3 |
| 4 |
=
| 3 |
| 4 |
(2)
| 15 |
| 7 |
| 9 |
| 8 |
| 5 |
| 9 |
| 3 |
| 8 |
=
| 15 |
| 7 |
| 5 |
| 8 |
| 3 |
| 8 |
=
| 15 |
| 7 |
| 5 |
| 8 |
| 3 |
| 8 |
=
| 15 |
| 7 |
=3
| 1 |
| 7 |
(3)(
| 11 |
| 4 |
| 4 |
| 7 |
| 5 |
| 7 |
| 3 |
| 2 |
=(
| 11 |
| 4 |
| 4 |
| 5 |
| 3 |
| 2 |
=
| 39 |
| 20 |
| 3 |
| 2 |
=
| 13 |
| 10 |
(4)[2-(
| 8 |
| 5 |
| 1 |
| 3 |
| 15 |
| 4 |
=[2-
| 29 |
| 15 |
| 15 |
| 4 |
=
| 1 |
| 15 |
| 15 |
| 4 |
=
| 1 |
| 4 |
(5)(
| 5 |
| 3 |
| 2 |
| 7 |
=
| 5 |
| 3 |
| 2 |
| 7 |
=35-6,
=29;
(6)
| 3 |
| 8 |
| 8 |
| 3 |
=
| 45 |
| 8 |
| 9 |
| 8 |
=4.5;
(7)[
| 8 |
| 15 |
| 4 |
| 5 |
| 3 |
| 10 |
| 15 |
| 14 |
=[
| 8 |
| 15 |
| 1 |
| 2 |
| 15 |
| 14 |
=
| 1 |
| 30 |
| 15 |
| 14 |
=
| 1 |
| 28 |
(8)
| 1 |
| 6 |
| 2 |
| 3 |
| 4 |
| 5 |
| 8 |
| 15 |
=
| 1 |
| 6 |
| 2 |
| 3 |
| 4 |
| 15 |
=
| 1 |
| 6 |
| 2 |
| 3 |
| 15 |
| 4 |
=
| 5 |
| 12 |
点评:此题要依据四则混合运算法则进行计算,同时认真分析各组数据,能简便计算的要简便计算.
练习册系列答案
相关题目