I mean- is there a universe where U see all the mathematical formulas that ever existed??? No! It is just a imaginary tool humans made to understand the universe.
I can observe that 1 dorito plus 2 doritos equals 3 doritos. 1 dorito plus 2 doritos will always be 3 doritos. Is math really unobservable? If math was not observable, 1 dorito plus 2 doritos might equal 3 doritos sometimes but other times it might not. ^-c^