Melodic minor scales are built with a W–H–W–W–W–W–W–H step pattern—W is a whole-step (two frets) and H is a half-step (one fret). The A melodic minor scale is spelled A–B–C–D–E–F#–G#–A, or 1–2–b3–4–5–6–7–8 in scale tones. (In classical theory, the melodic minor scale has a separate formula for its ascending and descending forms. For our purposes—as is often the case in jazz—we’re using the ascending form for both directions, not the descending form, which would be the same as an A natural minor.)