Your friend eats 3/4 of what was left? (If you mean 3/4 of what you previously ate, the answer would be different.)
3/4 of 2/3 is just (3/4)*(2/3) which is 1/2. This is the part newly eaten by your piggy friend. You now have 2/3-1/2 left. Getting the common denominator, that's 4/6-3/6=1/6
Answer: 1/6 pan left
