Today I learned some Roman Numerals. One is; I, two is; II, three is; III, four is; IV, five is; V, and so on. In four it has the Numerals 5 and 1. WHY? Because the first Numeral tot he left of the Numeral farthest right, gets subtracted. So, 5-1= 4. Every Numeral to the right of the Numeral is added.