What is a permutation?

Can you explain what a permutation is?

Sure! A permutation is an arrangement of objects in a specific order. For example, the different ways to arrange the letters in the word 'cat'.

How do you calculate the number of permutations?

To calculate permutations, you can use the formula n! / (n - r)!, where n is the total number of items, and r is the number of items to arrange.

Can you give me an example with numbers?

Of course! If you have 3 items (1, 2, 3) and want to arrange 2 of them, the permutations would be 3! / (3 - 2)! = 3! / 1! = 6.

What about combinations? How are they different?

Great question! Combinations refer to the selection of items without regard to the order, while permutations consider the order.