29×29/28+27×27/28.

问题描述:

29×

29
28
+27×
27
28

29×

29
28
+27×
27
28

=(28+1)×
29
28
+(28-1)×
27
28

=28×
29
28
+1×
29
28
+28×
27
28
-1×
27
28

=29+
29
28
+27-
27
28

=(29+27)+(
29
28
-
27
28
),
=56+
1
14

=56
1
14