While Amber, Sam and Uncle Zak are collecting junk for recycling they discover an old dartboard and darts. Zak shows them how to play and suggests that they try to make 20 with two darts. Amber does well when asked what number she needs to turn a score of 7 into 20. Numberella joins the game and they vary the rules to include starting at 20 and counting back. The children find this more difficult, but with help, find that once they know one addition fact they can make another addition and two corresponding subtractions.