用简便方法计算.①27+35-27+35②713-56+613-16③517+316+1217.-数学

题目简介

用简便方法计算.①27+35-27+35②713-56+613-16③517+316+1217.-数学

题目详情

用简便方法计算.
2
7
+
3
5
-
2
7
+
3
5

7
13
-
5
6
+
6
13
-
1
6

5
17
+
3
16
+
12
17
题型:解答题难度:中档来源:不详

答案

class="stub"2
7
+class="stub"3
5
-class="stub"2
7
+class="stub"3
5

=(class="stub"2
7
-class="stub"2
7
)+(class="stub"3
5
+class="stub"3
5
),
=0+class="stub"6
5

=class="stub"6
5


class="stub"7
13
-class="stub"5
6
+class="stub"6
13
-class="stub"1
6

=class="stub"7
13
+class="stub"6
13
-(class="stub"5
6
+class="stub"1
6
),
=1-1,
=0;

class="stub"5
17
+class="stub"3
16
+class="stub"12
17

=class="stub"5
17
+class="stub"12
17
+class="stub"3
16

=1+class="stub"3
16

=1class="stub"3
16

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