计算:113-712+920-1130+1342-1556+1772-1990=______.-数学

题目简介

计算:113-712+920-1130+1342-1556+1772-1990=______.-数学

题目详情

计算:1
1
3
-
7
12
+
9
20
-
11
30
+
13
42
-
15
56
+
17
72
-
19
90
=______.
题型:填空题难度:中档来源:不详

答案

1class="stub"1
3
-class="stub"7
12
+class="stub"9
20
-class="stub"11
30
+class="stub"13
42
-class="stub"15
56
+class="stub"17
72
-class="stub"19
90

=1+class="stub"1
3
-(class="stub"1
3
+class="stub"1
4
)+(class="stub"1
4
+class="stub"1
5
)-(class="stub"1
5
+class="stub"1
6
)+(class="stub"1
6
+class="stub"1
7
)-(class="stub"1
7
+class="stub"1
8
)+(class="stub"1
8
+class="stub"1
9
)-(class="stub"1
9
+class="stub"1
10
),
=1+class="stub"1
3
-class="stub"1
3
-class="stub"1
4
+class="stub"1
4
+class="stub"1
5
-class="stub"1
5
-class="stub"1
6
+class="stub"1
6
+class="stub"1
7
-class="stub"1
7
-class="stub"1
8
+class="stub"1
8
+class="stub"1
9
-class="stub"1
9
-class="stub"1
10

=1-class="stub"1
10

=class="stub"9
10

故答案为:class="stub"9
10

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