Haha. I was wondering what your Mom's had against mathematical consonants so I checked for another meaning.
I did not know that Europe numbered food additives as E-numbers. That sounds reasonable. Over here across the pond they try to confuse us by referring to ingredients by complicated sounding chemical names. Like we've never read a chemistry book. The nerve.
It doesn't work though, because we have read a chemistry book. And, the internet is useful for more than keeping up with the Kartrashians.
Your mother sounds like a wise woman.