Main problem i am having is that with the program it can have a 2 string equation - eg 25 R or 25 S (Reciprocal and Squareroot)

or a 3 string equation where the second string will be a number and the third string will be the operator. eg 10 5 + or -10 20 -

I am not sure how to get this to work - i can get the coding to work if its just the 2 string equation but then if it is a 3 string equation i come unstuck.

Can anyone provide some assistance please.