# Math

## Numbers

Number is a mathematical object used to count, measure, and label.

The original examples are the natural numbers 1, 2, 3, 4, and so forth.

In mathematics, the notion of a number has been extended over the centuries to include 0, negative numbers, rational numbers such as one half, real numbers such as the square root of 2 and π, and complex numbers which extend the real numbers with a square root of −1.

## Geometry

Geometry is a branch of mathematics that studies the sizes, shapes, positions angles and dimensions of things.

Flat shapes like squares, circles, and triangles are a part of flat geometry and are called 2D shapes.

These shapes have only 2 dimensions, the length and the width.

## Wave

Wave is a propagating dynamic disturbance (change from equilibrium) of one or more quantities, sometimes as described by a wave equation.

In physical waves, at least two field quantities in the wave medium are involved.

Waves can be periodic, in which case those quantities oscillate repeatedly about an equilibrium (resting) value at some frequency.

When the entire waveform moves in one direction it is said to be a traveling wave; by contrast, a pair of superimposed periodic waves traveling in opposite directions makes a standing wave.

## Roman numerals

Roman numerals are a numeral system that originated in ancient Rome and remained the usual way of writing numbers throughout Europe well into the Late Middle Ages.

The use of Roman numerals continued long after the decline of the Roman Empire.

From the 14th century on, Roman numerals began to be replaced by Arabic numerals; however, this process was gradual, and the use of Roman numerals persists in some applications to this day.

## Fractal

Fractal is a subset of Euclidean space with a fractal dimension that strictly exceeds its topological dimension.

Fractals appear the same at different scales.

Fractals exhibit similar patterns at increasingly smaller scales (expanding symmetry).