bash man page needs more examples...(i.e. >0)

[Linda Walsh]

reading the section no constants:
      Constants with a leading 0 are interpreted as octal numbers.  A 
leading
      0x  or  0X  denotes  hexadecimal.   Otherwise,  numbers  take  
the form
      [base#]n, where base is a decimal number between 2 and 64  
representing
      the arithmetic base, and n is a number in that base.  If base# is 
omit-
      ted, then base 10 is used.  The digits greater than 9  are  
represented
      by  the  lowercase  letters,  the  uppercase letters, @, and _, 
in that
      order.  If base is less than or equal to 36,  lowercase  and  
uppercase
      letters may be used interchangeably to represent numbers between 
10 and
      35.

declare -i var
var=0x20; echo $var
32

ok, fine, now lest try decimal, digits > 9 represented by lower case, so
'a' seems like it would be used for base

var=a32 ;echo $var
0
                                    #nope, maybe I have to have a 
leading 0...
var=0a32; echo $var
-bash: 0a32: value too great for base (error token is "0a32")
                                     #nope, maybe he mean for me to 
actually use # after
the base...?

var=a#32; echo $var
-bash: a#32: syntax error: invalid arithmetic operator (error token is 
"#32")

                                    #nep!... Geez, Um, just exactly  
HOW should one
determine the syntax from the above?

???
thanks (I think?   though a few examples would be nice in several 
areas...)...