(1/2-1/4)+(1/4-1/6)+(1/6-1/8)+……+(1/48-1/50)
=1/2-(1/4-1/4)-(1/6-1/6)-……-(1/48-1/48)-1/50
=1/2-1/50
=25/50-1/50
=24/50
=12/25
(1/2-1/4)+(1/4-1/6)+(1/6-1/8)+……+(1/48-1/50)
=1/2-(1/4-1/4)-(1/6-1/6)-……-(1/48-1/48)-1/50
=1/2-1/50
=25/50-1/50
=24/50
=12/25