I assume it says "forty" which is enough to avoid this kind of ambiguity. Edit: Actually no, quoting the official website [1]: > A candidate's 40th birthday m

I assume it says "forty" which is enough to avoid this kind of ambiguity. Edit: Actually no, quoting the official website [1]: > A candidate's 40th birthday must not occur before January 1st of the year of the Congress at which the Fields Medals are awarded. [1] http://www.mathunion.org/general/prizes/fields/details/ http://www.mathunion.org/general/prizes/fields/details/