Find the LCM(lowest common multiple) of 3 and 8 which is 24
Multiply the denominator of 2/3 by 8 and 1/8 by 3
Whatever you do to the denominator you have to do to the numerator, so you also have to multiply the numerator of 2/3 by 8 and 1/8 by 3 = 2 16/24 + 4 3/24
Add the whole numbers (4+2= 6)
Add the fractions (16/24 + 3/24= 19)
Put them together and the answer is 6 19/24
I can't really explain things properly, but I hope it helps