Practical math is not art. That is to say, the math you use to calculate your taxes or bank balance or other every day life math. This type of use is fundamentally the same as writing emails or drawing out diagrams on the board at work. Neither of these latter two are considered any form of art such as literature or fine art. They are practical applications of writing and drawing in everyday life.
You are conflating two different things. Practical use versus theoretical use.
For example, when you think about theoretical math, such as what Einstein envisioned, then it is very much in the realm of art. It takes creativity, imagination and envisioning complex design flows to create the math theories that will take humanity to the next level. There is a massive difference between adding numbers to balance your bank book and building complex designs using mathematics to describe the functioning of the universe. The latter is very much considered an art, though some prefer the term genius.