Roman Numerals / 11

11 in Roman Numerals

XI

11 = X (10), I (1). That's XI, purely additive. 11 splits into 1 ten (X), 1 (I), together forming XI. One below 11 is X (10); one above is XII (12). At 2 symbols, XI is compact for 11. 11: 2 Arabic digits, 2 Roman symbols, for 11. In binary, 11 is 1011, 4 bits long for 11.