The BASIC Stamp solves math problems in the order they are written; from left to right. The
result of each operation is fed into the next operation. So to compute -
Code:
    12 + 3 * 2 / 5

...the BASIC Stamp goes through a sequence like this:

    12 + 3 = 15
    15 * 2 = 30
    30 / 5 = 6
Unlike the BASIC Stamp, the PBP Compiler performs all math operations in full hierarchal
order. This means that there is precedence to the operators.

Multiplies and divides are performed before adds and subtracts, for example:
Code:
    12 + 3 * 2 / 5

...PBP goes through a sequence like this:

    3 * 2 = 6    multiply first
    6 / 5 = 1.2  divide second (the .2 is lost)
    12 + 1 = 13  add last
Forcing the addition first with parenthesis like: (12 + 3) * 2 / 5 would return the correct
result. Good stuff to remember when porting BASIC Stamp code over to PBP.

I haven't played with a BASIC Stamp in years, but once I looked in the Stamp editor help
file under PBASIC Operators, it was obvious. I'm glad you got it working. Looks like a
fun project.

Maybe you could post your final version in the code examples section? Could save someone
else using the Parallax RFID components with PBP a lot of head-scratching...;o}