Huge increase in mathematical procedure (14)
I believe the answer is:
multiplication
This might be a double definition.
'huge increase' is the first definition.
'multiplication' can be an answer for 'increase' (multiplication is a kind of increase). I'm not certain of the 'huge' bit.
'mathematical procedure' is the second definition.
'multiplication' can be an answer for 'procedure' (multiplication is a kind of procedure). I'm not sure about the 'mathematical' bit.
'in' is the link.
Can you help me to learn more?
(Other definitions for multiplication that I've seen before include "Method of making product" , "X may stand for this" , "Mathematical operation" , "Generation" , "does perform particularly well?" .)