She arrived at the monochord like a detective, headphones on, ears tuned — a thirteen-year-old ready to hear numbers sing. The pre-unit check asked her to blend listening and ratio reasoning; she answered with calm curiosity. Guided by Pythagorean stories and hands-on monochord demos, frequency relationships began to click: she identified the 1:2 octave, matched expected ratios to measured tones, and adjusted predictions by ear. Her responses showed clear reasoning, budding disciplinary vocabulary and tidy ratio notation. She collaborated thoughtfully, explaining steps aloud and comparing outcomes. This work demonstrates foundational proficiency with octave relations, accurate musical language, and an eagerness for deeper study of tuning systems, interval construction and reflective listening. In short, she entered ready, engaged throughout, and leaves the pre-unit poised to sharpen technique and theory. Expect steady progress as she explores more complex intervals and tuning practices. Her next steps include measuring ratios and refining intonation daily.