Since 1/2 plus 4/6 is bigger than a whole, we can’t have 1/2 of 54 (27) and 4/6 of 54 (36) because 27+36=63 and we only have 54 gumballs! So I think the question might be that 4/6 of half the gumballs are blue. So we need 4/6 of 27. 4/6 can be reduced to 2/3, and since 1/3 of 27 is 27/3=9 then 2/3 is 18. The remaining 9 must be red. So we have 27 yellow, 18 blue and 9 red, making 54 altogether.