Funny, I don’t remember reading that in the rule book

Milo, playing with some matching memory cards… “Mom, what’s five plus six?”

Me: “Eleven.”

Milo: “That means I can only use the swimming butterfly card 11 times.”

Me: “Oh? Why?”

Milo: “Because it has triple fire power and is really dangerous so you can only use it in times of emergencies. Blam! Pow!”