Map scale-degree numbers to real chords, in any key.
Session musicians in Nashville often write chord charts using numbers instead of letter names — 1, 2, 3, 4, 5, 6, 7 — for each note of the scale, instead of writing "C" or "G". A minor chord gets a small "m" (like 2m), and the 7th degree usually gets "dim".
The whole point: the SAME numbers work in every key. A "1–4–5" progression is always built the same way, whether you're playing in C or in Eb — so a band can change key on the spot without re-learning the song.
Key — this is your difficulty. More sharps/flats = harder.
Tap a chord below, then tap the number you think it belongs to