Спримером 1+1/10*11+1/11*12+1/12*13+1/13*14+1/14*15+1/15*16

=1+(1/10*11+1/11*12)+(1/12*13+1/13*14)+(1/14*15+1/15*16) =1+22/10*11*12+26/12*13*14+30/14*15*16=1+1/5*12+1/7*12+1/7*16= 1+12/5*7*12+1/7*16=1+1/5*7+1/7*16=1+21/5*7*16=1+3/80=1  3/80