To answer the question of how many 4s are in a deck of cards, we must first understand the makeup of a standard deck of 52 playing cards.

A deck of cards is made up of four suits – hearts, diamonds, clubs, and spades – with each suit containing 13 cards. The cards in each suit are numbered 2 through 10, with the remaining cards being the face cards: jack, queen, king, and ace.

Now, we need to determine how many 4s are in a deck of cards. Since there are four suits in a deck, there will be four 4s in each suit, for a total of 16 4s in the entire deck of cards.

To understand why there are 16 4s in the deck, we can use the multiplication principle of counting. The multiplication principle states that if there are m ways to perform one task and n ways to perform another task, then there are m x n ways to perform both tasks together.

In this case, there are 4 suits and one 4 in each suit, so there are 4 x 1 = 4 ways to choose a 4 from the suits. We then multiply this by the total number of cards in a suit, which is 13. **Therefore, there are 4 x 13 = 52 cards in a deck, and 16 of those cards are 4s.**

In summary, there are 16 4s in a standard deck of cards, and this can be determined by understanding the makeup of a deck of cards and using the multiplication principle of counting to calculate the total number of 4s in the deck.