In Roman numerals, 601 is written as "DCI." The letters 'D,' 'C' and 'I' stand for 500, 100 and one respectively. The system of Roman numerals includes a set of seven symbols to write large and small numbers; however, writing large numbers is more difficult.
Symbols must not be repeated more than three times. A larger symbol to the left of a smaller symbol means that both must be added together. A larger symbol to the right of a smaller symbol means that the smaller number is to be subtracted from the larger number. Roman numerals are no longer in use except for when teaching children in primary classes and on the faces of old clocks.