This is the combination of 52 items taken 5 at a time. 52C5= 52(51)(50)(49)(48)/(5)(4)(3)(2)(1).
The following Desmos graph has a row that shows the "formula" that is used to calculate combinations. There is also a Desmos function for calculating combinations which is also shown.
desmos.com/calculator/srooowtjgd
Calculating this number is going to lead to questions like this:
- What is the probability of getting dealt a flush?
- Getting dealt a full house?
The number calculated above is going to be the denominator of the sample questions above.