Jeff has 2/3 gallon of sherbet. he gives each of his friends 1/12 gallon

He has 1/2 of a gallon remaining

Suppose he gives his x friends 1/12 gallon from this 2/3 gallon of sherbet.

Divide 2/3 gallon by 1/12 gallon:     

2
--
3
gallon per friend  
1
---
12

2     12
-- * = 8 friends get 1/12 gallon of sherbet each.
3      1

Check:  Does (1/12) times 8 equal (2/3) gallon?   YES