## Part 1 - Dice, Cards, and Probability - Foundation

This blog post is the first for a possible series of posts concerning dice and card probability. While I do not present any new information, I am posting this so that the basics will be covered.

I plan on looking at d20, d6, d100, and card decks in the future.

### What is probability?

Probability is the chance or likelihood that an event or situation will happen or occur.

### How do you simulate random occurrence in gaming?

In RPGs, probability and random occurrence is simulated through multiple means, methods, tool, or medium that a random probability is generated, called Random Number Generator (RNG) in computer science. Dice are the most commonly used tool to generate random numbers. Two other popular physical RNGs are a deck of cards and a computer program, app, or website. Coins, rock-paper-scissors, or guessing a number between _ and _ are other less popular methods.

### Expressing the probability of single occurrence using notation.

In math, basic probability can be expressed in terms of "how many times occurrences" out of "how many times attempted".

let # = number
let O= # of occurrences
let T= total number of tries

successful O out of total T
"out of" keyword O out of T
Colon O:T
Division notation O/T or O÷T. It's best to simplify fractions.

Since probability can be expressed as a division, you can find a decimal between 0 and 1 by dividing the total number into the number of occurrences.

And that number can be converted into a percentage (%).

#### An example of expressing the probability of getting 'heads' on a coin flip.

For example: A coin flip is either heads or tails.
The chance of getting heads is one occurrence out of two: either heads or tails.
1 out of 2
1:2
1/2
To convert the chance of
1/2 or 1 ÷2 = 0.5
0.5=50% chance

#### Combinations Formula

! = factorial symbol
let n = number of items
let r = number of items being chosen at a time
nCr = n!/r! * (n-r)