There are infinitely many numbers, and infinitely many ways to combine and manipulate those numbers.
Mathematicians often represent numbers in a line. Pick a point on the line, and this represents a number.
At the end of the day, though, almost all of the numbers that we use are based on a handful of extremely important numbers that sit at the foundation of all of math.
What follows are the eight numbers you actually need to build the number line, and to do just about anything quantitative.