Efectuati:

1+2+3+...+100
___________
2+4+6+...+200


Răspuns :

1+2+3+...+100=100x101/2=5050
2+4+6+...+200=2(1+2+3+...+100)=2x5050=10100
5050/10100=1/2
(1+2+3+...+100)/(2+4+6+...+200)=

=(1+2+3+...+100)/2(1+2+3+...100)

=1/2