For this method, we need to be familiar with the
natural minor and
harmonic minor scales, which can be thought of as the predecessors of the melodic minor scale. In my experience, this method is more practical than just memorizing a formula of whole steps and half steps as it is more meaningful for the brain, which makes it easier to remember (at least for me!).The idea here is to take the harmonic minor scale as our starting point and to modify it slightly on the way up (ascending). Then, just use the natural minor scale on the way down (descending).