To compare the fractions we need to find a common denomanator. This means we need to find a common number (to the denomanator) in each number set of times tables. In this case we can use 6 as a common denomator.
One of out fractions is already out of 6 so we just need to convert the other one. We can just double 4/3 to give us 8/6.
We can now compare the data, we have 8/6 and 8/6. These fractions show that both John and Mya use the same amount of milk for their recipies, this being 8/6 or 1 1/3 as a mixed number.