Calculati urmatoarele sume: a)2/25+4/25+6/25+.......+50/25
b)3/51+6/51+9/51+.........+150/51
c)11/50+12/50+13/50+......+60/50
d)47/46+48/46+49/46+.......+97/46.

Indicatie:La primele doua puncte,vom incepe prin a da factor comun.La urmatoarele doua vom desface fiecare numarator in suma.