1+1÷72+2+1÷90+3+1÷110+4+1÷132+5+1÷156=1+2+3+4+5+1÷72+1÷90+1÷110+1÷132+1÷156=15+(1/8-1/9)+(1/9-1/10)+(1/10-1/11)+(1/11-1/12)+(1/12-1/13)=15+1/8-1/13=15+5/104