Suppose I have 10 bitcoin and I want to send 1 bitcoin to you. My understanding is that this transaction would create three entries in the blockchain as follows:
Entry 1: Spends my 10 bitcoin. I will call this my "spend" address.
Entry 2: Sends 1 bitcoin to your recipient address.
Entry 3: Returns 9 bitcoin to me. I will call this my "change" address.
Don't forget to mention transaction/TX fee on your talk. Some people consider TX fee on Bitcoin isn't cheap.