The conversation between human and AI assistant.
Why does zero factorial (0!) equal one (1)?
Can you give me an example of how it helps in a formula?
Sure! One example is the formula for calculating the total number of combinations of n objects taken r at a time, which is given by the equation n!/((n-r)!r!). This formula gives the correct result when n is 0 and r is 0 if we define 0! as 1.