Word Forms of Teen Numbers
From Anne-Marie Morey's "How to End Number Switching":
"The teen numbers actually make a lot of sense if we look at the words’ origins in Old English. By visiting the Etymology Dictionary we discover:
- The morpheme “teen” means ten more than. “Thirteen” then means three and ten more. This pattern explains: thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, and nineteen.
- Eleven also comes from Old English and means one left (over ten).
- Similarly, twelve means two left (over ten).
The morphology of number words actually helps build mathematical understanding!"