Mathematician heads to Egypt upon learning exchange rates (5)
I believe the answer is:
euler
'mathematician' is the definition.
(I know that Euler is a mathematician)
'heads to egypt upon learning exchange rates' is the wordplay.
'heads to' says to take the initial letters (I've seen 'heading to' mean this (the head of the word)).
The initial letters of 'egypt upon learning exchange rates' is 'EULER'.
(Other definitions for euler that I've seen before include "Swiss scientist" , "Leonhard -, C-eighteen Swiss mathematician" , "18th-century Swiss mathematician and physicist" , "Leonhard -, Eighteenth century Swiss mathematician" , "calculating foreigner" .)