先比一比:上2×上1______上2-上1;上1×上4______上1-上4;上4×上5______上4-上5;上5×上6______上5-上6;再算一算:上2×上1+上1×上4+上4×上5+上5×上

题目简介

先比一比:上2×上1______上2-上1;上1×上4______上1-上4;上4×上5______上4-上5;上5×上6______上5-上6;再算一算:上2×上1+上1×上4+上4×上5+上5×上

题目详情

先比一比:
2
×
1
______
2
-
1

1
×
4
______
1
-
4

4
×
5
______
4
-
5

5
×
6
______
5
-
6

再算一算:
2
×
1
+
1
×
4
+
4
×
5
+
5
×
6
+
6
×
7
+
7
×
8
+
8
×
9
+
9
×
上0
题型:解答题难度:中档来源:不详

答案

class="stub"1
2
×class="stub"1
3
=class="stub"1
6
class="stub"1
2
-class="stub"1
3
=class="stub"1
6

所以class="stub"1
2
×class="stub"1
3
=class="stub"1
2
-class="stub"1
3

同理可得:class="stub"1
3
×class="stub"1
9
=class="stub"1
3
-class="stub"1
9

class="stub"1
9
×class="stub"1
5
=class="stub"1
9
-class="stub"1
5

class="stub"1
5
×class="stub"1
6
=class="stub"1
5
-class="stub"1
6


class="stub"1
2
×class="stub"1
3
+class="stub"1
3
×class="stub"1
9
+class="stub"1
9
×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

=class="stub"1
2
-class="stub"1
3
+class="stub"1
3
-class="stub"1
9
+…+class="stub"1
9
-class="stub"1
10

=class="stub"1
2
-class="stub"1
10

=class="stub"2
5

故答案为:=,=,=,=.

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