Some Confusion about Tithing

So Jacob's birthday is coming up and he got a card in the mail with money in it! He was really excited about it. Dad mentioned that he could pay tithing now that he had his own money. He looked a little confused so Mark followed up with a simple explanation that we give 10% of our money to Heavenly Father. Jacob accepted that and without further ado started throwing one of his dollar bills into the air! Finally in exasperation he looked up and said "Heavenly Father, you're gonna have to come down here and get it"