1/2+3/4+5/6+7/8+9/10=1-1/2+1-1/4+1-1/6+1-1/8+1-1/10=5-(1/2+1/4+1/6+1/8+1/10)=5-(60+30+20+15+12)/120=5-137/120=463/120
115
