when adding/subtracting fractions, u have to find the common denominator. In this problem, u have to find the common denominator of 3 and 12. What number goes into both 3 and 12 ? That number is 12.
2/3 = 8/12
11/12 = 11/12
now we can add.....8/12 + 11/12 (just add the numerators, the denominators stay the same) = 19/12 which equals 1 7/12