题目内容
能简算要简算: 12×(
|
24×
|
| ||||||||||||||
86×
|
|
|
分析:12×(
+
)、
×
+
÷7可据分配律进行简算;
×
÷
可据结合律进行简算;86×
可按85×
+
进行简算;其余据四则混合运算法则进行计算即可.
2 |
3 |
1 |
6 |
9 |
17 |
1 |
7 |
5 |
17 |
7 |
10 |
5 |
16 |
21 |
32 |
4 |
85 |
4 |
85 |
4 |
85 |
解答:解:(1)12×(
+
)
=12×
+12×
,
=8+2,
=10;
(2)24×
-
=
-
,
=2
;
(3)
×
÷
=
×(
÷
),
=
×
,
=
;
(4)86×
=85×
+
,
=4+
,
=4
;
(5)
×
+
÷7
=
×
+
×
,
=(
+
)×
,
=
×
,
=
;
(6)
÷(
+
)
=
÷
,
=
.
2 |
3 |
1 |
6 |
=12×
2 |
3 |
1 |
6 |
=8+2,
=10;
(2)24×
5 |
36 |
3 |
8 |
=
10 |
3 |
3 |
8 |
=2
23 |
24 |
(3)
7 |
10 |
5 |
16 |
21 |
32 |
=
7 |
10 |
5 |
16 |
21 |
32 |
=
7 |
10 |
10 |
21 |
=
1 |
3 |
(4)86×
4 |
85 |
=85×
4 |
85 |
4 |
85 |
=4+
4 |
85 |
=4
4 |
85 |
(5)
9 |
17 |
1 |
7 |
5 |
17 |
=
9 |
17 |
1 |
7 |
5 |
17 |
1 |
7 |
=(
9 |
17 |
5 |
17 |
1 |
7 |
=
14 |
17 |
1 |
7 |
=
2 |
17 |
(6)
2 |
5 |
3 |
4 |
2 |
5 |
=
2 |
5 |
23 |
20 |
=
8 |
23 |
点评:完成本题要认真分析各组数据,运用适当的简算方法计算.

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