Examples of equations using the keyboard only:

Agree with those you will communicate with how you want to express mathematical notation. There is no one right way to do fthis as long as you are all consistent.  The carrot symbol usually precedes an exponent. x^3 is x cubed.

y = LIM: x->5: f(x) means y = the limit as x approaches 5 of the funtction F(x).

y = (d2/dx) f(x) means y = the second derivative with respect to x of the  function f(x).

y = (d3/dx) f(x) means y = the third derivative with respect to x of the function f(x).

y = INT:{L5}:{U7}: f(x) dx

means y = the integral from lower bound 5 to  upper bound 7 of the function f(x) with respect to x.

In print books the lower bound is expressed as a subscript. The upper bound is expressed as a superscript. You may choose to do it this way.

y = INT: subscript 5 superscript 7 f(x) dx.

Exponents are also usually expressed as a supersscript.

Assume that you are sending what you write to a person capable of forgiving minor syntax errors rather than to a piece of software  which will not forgive minor errors.

A professor with several degrees in mathematics will understand immediately what you mean, and will probably suggest  improvements.

This is only a start. Don't ask your professor to learn Braille.  I recommend that you not put a piece of software between you and the person you are trying to communicate with. Such a piece of software will act  like a precompiler that your input has to satisfy before your message reaches your audience. Just a suggestion. Do what you want.

Once everybody has agreed to thses notations, you can write regular expressions to have what you write read as it would be spoken in a math class.

Good luck.