do 1/3-1/2
to do this find lcm and multiply by fractions
lcm (least common multiple) in this case is 6 so change the denominators of both fractions to 6 by multiplying 1/3*2/2 and 1/2*3/3
you'll get 2/6-1/6=1/6
1/6 cup of oil is the answer
tell me if u need me to explain it a different way