This is one that's been messing with my mind for a bit. Right, so say Peter wants to send 6XBT to Sally. The sum of none of the transactions in Peter's wallet adds up to exactly the desired 6XBT so he sends 7 instead and receives one 1XBT in change from Sally. Now what happens if Sally doesn't have exactly 1XBT in her wallet to send Peter? Would the change transaction then be, say, 1.5XBT and then she gets 0.5XBT back in change from Peter and so it goes on until either of them have the exact amount to send back. I assume this doesn't happen, but then could you please explain to me what does happen.