How to find answer to 5lb -1 2/3 -2 3/4 = what

Question

I have 5 lbs of sugar I use 1 2/3 lbs for muffins & 2 3/4 for cake, how much is left

Answer 1

5 - 1 2/3 - 2 3/4

= 5 - 5/3 - 11/4

put the3 terms over a common denominator

= 60/12 - 20/12 - 33/12

= (60-20-33)/12

= 7/12 lb of sugar left

= a little over half a pound left