Legit Math Software for Mac Users that is Free for H.S. Students

$$\textbf{Question:}$$ Is there a type of math software for $$\underline{\text{Mac}}$$ that is $$\underline{\text{free}}$$ for students that allows easy computation of functions like below? [Note the division symbol goes horizontal automatically and I can shorthand variables as numbers.]

I have found no such luck downloading math software for Mac computers, and I find calculators miserable to type in complicated functions like these. I need an alternative solution.

Any help would be greatly appreciated!