A =    + + + +   51 52 53 1001 1 1 1 1 1 1 1 1 1 1 1 1 1 1

2012 ...

A =    + + + +   

51 52 53 100

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

... .... 2 ...

B = − + − + + − =   + + + + +   −   + + + +  

   

1 2 3 4 99 100 1 2 3 99 100 2 4 6 100

1 1 1 1 1 1 1 1 1 1 1 1

B =    + + + +       − + + + +    = + + + +

... ... ...

1 2 3 100 1 2 3 50 51 52 53 100

A

Khi đó : 2012

1 2012

B = =

A = + + + +