Utility-Preserving De-Identification for Math Tutoring: Investigating Numeric Ambiguity in the MathEd-PII Benchmark Dataset. - Zhuqian Zhou; Kirk Vanacore; Bakhtawar Ahtisham; Jinsook Lee; Doug Pietrzak; Daryl Hedley; Jorge Dias 003; Chris Shaw; Ruth Schäfer; René F. Kizilcec (CoRR, 2026)