Mathematics is often described as universal because it is experienced by everyone and it is everywhere.

Filling in the blank

For the sentence:

“Mathematics is ___ because it is experienced by everyone and it is everywhere.”

the most fitting and commonly used word is:

Mathematics is universal because it is experienced by everyone and it is everywhere.

People call mathematics “universal” since its ideas and patterns apply across cultures, languages, nature, technology, and daily life.

TL;DR: The blank is best filled with the word universal.