> most of the time, a deck of cards is shuffled using a riffle. Here’s a question: how many times do you have to riffle a deck of cards before it is completely

> most of the time, a deck of cards is shuffled using a riffle. Here’s a question: how many times do you have to riffle a deck of cards before it is completely shuffled? It’s a tricky one, but math has us covered: you need seven riffles.