Digital computers encode information using two stable states, commonly represented as $0$ and $1$. A bit is one binary digit, and a byte is $8$ bits. Larger units often scale by powers of two, so $1\,\text{KiB} = 1024\,\text{bytes}$ and $1\,\text{MiB} = 1024\,\text{KiB}$.

Unsigned integers encode only nonnegative values, while signed integers usually use two's complement. For an $n$-bit two's complement integer, the range is $-2^{n-1}$ to $2^{n-1}-1$. This representation simplifies arithmetic in hardware.

Many real numbers are stored in floating-point form, which trades exactness for a wide range of values. This is why $0.1 + 0.2$ can produce a value that is very close to, but not exactly, $0.3$ in many programming languages.