题目内容
(2012?河池模拟)计算下面各题,怎样简便就怎样计算.
×
+
+
-
×
-
÷
﹢
÷13.
2 |
3 |
7 |
3 |
4 |
5 |
4 |
9 |
25 |
17 |
1 |
3 |
9 |
8 |
5 |
8 |
12 |
13 |
8 |
7 |
7 |
8 |
分析:(1)先算乘法,再运用加法交换律简算;
(2)先算乘法,再根据连续减去两个数等于减去两个数的和;
(3)先把除法变成乘法,再运用乘法分配律简算.
(2)先算乘法,再根据连续减去两个数等于减去两个数的和;
(3)先把除法变成乘法,再运用乘法分配律简算.
解答:解:(1)
×
+
+
,
=
+
+
,
=
+
+
,
=2+
,
=2
;
(2)
-
×
-
,
=
-
-
,
=
-(
+
),
=
-1,
=
;
(3)
÷
﹢
÷13,
=
×
+
×
,
=(
+
)×
,
=1×
,
=
.
2 |
3 |
7 |
3 |
4 |
5 |
4 |
9 |
=
14 |
9 |
4 |
5 |
4 |
9 |
=
14 |
9 |
4 |
9 |
4 |
5 |
=2+
4 |
5 |
=2
4 |
5 |
(2)
25 |
17 |
1 |
3 |
9 |
8 |
5 |
8 |
=
25 |
17 |
3 |
8 |
5 |
8 |
=
25 |
17 |
3 |
8 |
5 |
8 |
=
25 |
17 |
=
8 |
17 |
(3)
12 |
13 |
8 |
7 |
7 |
8 |
=
12 |
13 |
7 |
8 |
7 |
8 |
1 |
13 |
=(
12 |
13 |
1 |
13 |
7 |
8 |
=1×
7 |
8 |
=
7 |
8 |
点评:完成本题要注意分析式中数据,运用合适的简便方法计算.
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