First you add 3/4 and 2/3 you but then do 3/4 2/3 you think what the both can go to is 12 the dominator is 12 then you time it by 3,4 because they both go to 12 then the 3 will be time 3 because 4 x 3 = 12 then you do it the top so 3x3 = 9 9/12 then you do the next one is2/3 do the same then will get 8/12 then you can subtract it 9/12 - 8/12 will gave you 1/12
