@inproceedings{pme336559-sommerhoffwhichitemcha,
  title={Which Item Characteristics Drive the Difficulty of Mental Addition and Subtraction Tasks},
  author={Sommerhoff, Daniel},
  booktitle={Proceedings of the International Group for the Psychology of Mathematics Education, Volume 1},
  year={2026},
  pages={1379--1386},
  publisher={Psychology of Mathematics Education (PME)},
  issn={2790-3648}
}