2.2 Binary Arithmetic and Hexadecimal

Notes

Binary addition works like decimal addition but carries when a column reaches 2. Hexadecimal (hex) is base 16 and uses digits 0-9 and letters A-F, where A = 10, B = 11, C = 12, D = 13, E = 14, F = 15.

• Binary rules: 0+0=0, 0+1=1, 1+1=10 (write 0, carry 1).
• Example: 0110 + 0011 = 1001 (6 + 3 = 9).
• One hex digit equals exactly 4 bits, so hex is a short way to write binary.
• Example: 1010 1111 in binary is AF in hex, because 1010 is A and 1111 is F.
• Hex to decimal: 2F = 2 x 16 + 15 = 47. Hex is often used for colors, such as #FF0000 for red.