To understand how we get these numbers, we have to look at each Roman numeral group individually: XXV: X (10) + X (10) + V (5) = 25 XXV: X (10) + X (10) + V (5) = 25 XIII: X (10) + I (1) + I (1) + I (1) = 13 XIV: X (10) + [V (5) - I (1)] = 14 Understanding the Rules of Translation