(3/5-1/2-7/12)*(60*3/7-60*1/7+60*5/7)=(3/5-1/2-7/12)*60*(3/7-1/7+5/7)=(3/5-1/2-7/12)*60*1=36-30-35=-29
=(3/5-1/2-7/12)*60*(3-1+5)/7=(3/5-1/2-7/12)*60*1=36-30-35=-29
