Dumb?

Every Sunday Dinner we go around the table to take turns telling what we learned about at church.

London: "We learned about Sherem."
Mom: "What about him?"
London: "I think it's in Jacob 7. He taught people to not believe in Christ and asked for a sign. So he was struck dumb....that means he couldn't count."

Pretty sure that's not the dumb the scriptures were talking about.