Question

112/13.20+112/20.27+...+112/62.69

 

Answer 1

=112/7.(7/13.20+7/20.27+...+7/62.69)

=16.(1/12-1/20+1/20-1/27+...+1/62-1/69)

=16.(1/13-1/69)=896/897