ALT ## binary numbers are hard to read 1101010111011001 1101010111001001 it's hard to tell if these are different! Also, binary numbers are too long: the number 4,000,000,000 is this in binary: 11101110011010110010100000000000 ## decimal has problems too 11010101 = 213 11000101 = 197 These are easier to read, but 213 and 197 look COMPLETELY different, even though the binary numbers only differ by 1 bit. This is bad if you're trying to think about the binary representation. ## hexadecimal makes binary data more readable Every hexadecimal digit represents 4 bits. So 1 byte (8 bits) is 2 digits. 1101 0101 1100 0101 d 5 c 5 * 11010101 = d5 * 11000101 = c5 it's much easier to see the similarities! ## there are 16 hex digits * decimal binary hex * 0000 0 0 * 0001 1 1 * (truncated) ## `0x` means it's hex person 1: "the ASCII code for space is 0x20" person 2: "that starts with `0x`, so it means 32 and not 20!" ## things hexadecimal is used for * color codes! (eg 0xFF00FF)