🚀 go-pugleaf

Hi everyone,

I'm a college student using the HP-20S. I've discovered that the
programs that I entered were lost after I loaded a built-in program.

Although the built-in program library contain six programs, it is
simply not enough for me. 

As  I know,  some calculators of this same class (e.g. HP 25) have
programming abilities but have no built-in program libraries.
But now with the built-in program library, I can't even save my
programs if I want to use a built-in one.

How can I save the programs in a "safe" place so that they won't be
lost after loading the built-in ones?

Whether there's solution to my problem or not, it would be very nice
of you to make a reply and tell me the fact so that I won't waste any
more time on programming this calculator.

Thanks
Mike