Answer aNumber - whatever class it belongs to, it is good
readFrom: aStream
Answer the number read from the rest of aStream, converted to an
instance of the receiver. If the receiver is number, the class of the
result is undefined – but the result is good.
readFrom: aStream radix: anInteger
Answer the number read from the rest of aStream, converted to an
instance of the receiver. If the receiver is number, the class of the
result is undefined – but the result is good.