Density refers to the mass of a substance per unit volume, usually represented by the symbol ρ, and the international unit is kilograms per cubic meter (kg/m³).

Cryptography is the technical science that studies how to encrypt and decrypt information. Simply put, it's about figuring out how to hide information so others can't understand it, and how to restore the hidden information.

Power refers to the form of a number multiplied by itself several times.

Area refers to the size of the space that an object's surface or a closed shape occupies on a two-dimensional plane, used to measure how much a 2D region is covered.

Area is how much space a shape takes up, while perimeter is how long the edges of the shape are. One is for measuring the size of the surface, the other is for the length of the edges, and their units are different too.

It's the basic unit of time in the International System of Units, symbolized as s.

Minkowski space is a spacetime in special relativity that consists of one time dimension and three spatial dimensions. It was first described by the Russian-German mathematician H. Minkowski (1864–1909).

August Ferdinand Möbius (November 17, 1790 – September 26, 1868) was a German mathematician and astronomer, born in Schulpforta, Saxony.

The Möbius strip is a magical paper loop with only one surface and one edge, discovered by the German mathematician Möbius in 1858. You just twist a regular strip of paper half a turn and stick the ends together, and then an ant can walk across the entire surface without ever flipping over.

Interest is the extra cost or earnings you get when you borrow or save money—basically, it's the fee for using money.