Notezi suma cu S,Observi ca
1/3+1/4+1/5+...+1/8>1/8+1/8+...+1/8 (de 6 ori)=6/8=3/4
Dec i
S>3/4
1/3+1/4+...+1/8<1/3+1/3+...1/3 (de 6 0ri)=6/3=2 S>2 =>
3/4<S<2
Ex 2 In mod asemanator notezi suma cu S
1/10+1/10+...+1/10(18 ori)=18/10=9/5>S
1/27+1/27+...+1/27 (de 18 ori)<18/27=2/3
Deci 2/3<S<9/5
