Which you said changed 130 years ago
The definition of Division changed more than 130 years ago. a+b/c+d originally meant (a+b)/(c+d), but that limited you to one division per expression, so they changed the definition to be a+b/c+d=a+(b/c)+d, which brought it into line with all the other operators - the underlying Maths never changed, just the way we write expressions did