Besides the humanities and arts most other subjects are built on a foundation of, and could not exist without maths, and that includes all of the sciences, engineering, business and computing to name but a few.

Mathematics is the language of the universe. Anything that concerns anything depends on mathematics at some point, even if it doesn't seem obvious. Take history as an example.

What if we want to say what year something happened? Well we need mathematical representation of it.

What if we want to say what the odds of an event happening were? Well we need maths to calculate them.

I defy anyone who claims that there is anything that is not at some point in its development contingent upon mathematics (besides mathematical fictionalists, but they can go frack themselves).

Mathematics is absolutely fascinating.

There are some small tribes that have only rarely seen modern society, and many of their number systems only go up to 4 or 5.

They see "1, 2, 3, 4, 5, a bunch, a lot, a really big amount"

Math is not necessary, but like art, it is interesting. Besides the most basic of calculation needed for money management, most mathematics is purely for art and decoration, perhaps just for the fun of doing math.