You will need to install a user script manager extension to install this script.
Using this will allow you to avoid the Pro block on MathPapa's calculator.
This was tested on the algebra calculator, it is unknown if it works for the other calculators.
Just use the calculator as you normally would, when you click the Calculate button, it will automatically remove the Pro limit for showing steps.
THIS DOES NOT UNLOCK PRO! THIS ONLY ALLOWS YOU TO SHOW THE SOLVING STEPS FOR EQUATIONS (which requires Pro)