During November, a 9th grade class collected 18 pounds 14 ounces of aluminum cans to be recycled, and a 10th grade class collected 22 pounds 1 ounce of aluminum cans. How many more ounces pf cans did the 10th grade class collect than the 9th grade class?

Question

During November, a 9th grade class collected 18 pounds 14 ounces of aluminum cans to be recycled, and a 10th grade class collected 22 pounds 1 ounce of aluminum cans. How many more ounces pf cans did the 10th grade class collect than the 9th grade class?

Answer 1

22lb 1oz = 21lb 17oz

now subtract 18lb 14oz
and you get 3lb 3oz = 3*16+3 = 51 oz

or, you could have converted all to oz at the start.
(22*16+1) - (18*16+14) = 51

or, in hexadecimal notation,
161 - 12E = 33