How many cards are less than 6 in a card set of 52?

In a standard deck of 52 playing cards, the ranks less than 6 are Ace, 2, 3, 4, and 5. Each rank has 4 cards (one for each suit: hearts, diamonds, clubs, and spades), so there are a total of 5 ranks multiplied by 4 cards per rank, which equals 20 cards that are less than 6.