Hexadecimal Fundamentals

Hexadecimal (base-16) uses sixteen digits: 0-9 and A-F. The letters A through F represent decimal values 10 through 15.

Each hex digit represents 4 binary bits. The hex digit F equals binary 1111 (decimal 15). The hex number 2A equals $2 \times 16^1 + 10 \times 16^0 = 32 + 10 = 42$ in decimal.

Why use hex? Binary numbers get long. The 8-bit binary 11010110 is just D6 in hex. Hex compresses binary while staying easy to convert. Programmers use hex for memory addresses, colors, and bit masks.