Question 949872
Let Or= original number
(Or+12-10)/2=8 Multiply each side by 2
Or+12-10=16 
Or+2=16 Subtract 2 from each side 
Or=14 
CHECK:(sort of)
Go through it backwards:
You end with 8 stamps,so before Jeff took half you had 16, before you gave Christine 10 you had 26 and before Jeff gave you 12 you originally had 14.