what do letters stand for in math? ​

Letters are most commonly used with Algebra and usually aren't that tricky when you get used to them.

Example.

             3x + 4x

if both numbers have matching letters you can add them together

              7x

Example2.

          4x + 5y

if numbers have different letters, you put the two letters together like this xy and add numbers.

             9xy

best to keep them in alphabetical order.

  also if you get a qs like this

      x * x

turn x into squared

X 2 

because deez nuts said so

if you are about my question below i mean letters like uknown s for example x or y

they stand for missing numbers