Little Johnny What’s The difference between

Little Johnny: ”What’s The difference between theoretically and realistically?”
Dad: ”It’s hard to explain. I tell you what, ask your mum if she would sleep with the milkman for a million quid and come and tell me what she says.”
A couple minutes later,
Little Johnny: ”She said, ‘yes’.”
Dad: ”Now ask your sister if she’ll sleep with the coal man for 2 million?”
A couple minutes later,
Little Johnny: ”She said, ‘yes’.”
Dad: ”That’s your answer son. Theoretically we are sitting on 3M, but realistically we are just living with 2 slags.”