pbasic 2.5 question.

Hello all,

I'm learning PBASIC 2.5 from a book called PROGRAMMING AND CUSTOMIZING
THE BASIC STAMP COMPUTER and I ran into this situation.  The following
code produces the output under it:

code----------------------------------------
' {$STAMP BS2}
' {$PBASIC 2.5}

_x  VAR Byte
_y  VAR Byte
_z  VAR Byte
_area VAR Word
_x = 20
_y = 30

B0 = 155
B1 = 220
W2 = B0 + B1

_area = _x*_y  'solve the area

DEBUG "the Area is ", DEC _area, "sq ft."
DEBUG CR, ? B0, ? B1, ? B2, ? W2
END
======================================
OUTPUT:
the Area is 600sq ft.
B0 = 88
B1 = 2
B2 = 20
W2 = 375
=====================================

My questions are:
-why is B1 = 2 when I declared it '220'?
-why is B2 = 20 when I didn't load it with any values?
-W2 is giving me the correct sum, but why are the B variables
displaying strange results?

Thanks,

-Alex