Maths is not an acronym, so the "a" does not intentionally represent a word or other linguistic entity. It is a contraction of "mathematics", which is derived from a combination of the greek and latin for study, learning, studiousness and science.
It doesn't stand for bananas.
3000
metre
elementary maths
It doesn't "stand for" anything. And wrong category.
maths economics comers
An unknown number.
LCM stand for Least Common Multiple
Base times Height
in maths it denotes as10
Terrible teachers failing maths
Right Hand Side [of an equation]