Roman numerals are a set of symbols that stand for numbers. The ancient Romans invented Roman numerals. Today, the Roman system is used to number the faces of clocks and to record dates on monuments and public buildings. It is also used to list topics in outlines.
All Roman numerals are written using seven basic symbols, either alone or in combination. These symbols are I (1), V (5), X (10), L (50), C (100), D (500), and M (1,000). A bar is sometimes placed over a Roman numeral to multiply it by 1,000. Roman numerals are written from left to right, using the principle of addition in most cases. A person first writes the thousands, then the hundreds, then the tens, and finally the units. To write 2,763, first write MM (2,000). Then write DCC (500 + 200 = 700). Next write LX (50 + 10 = 60). Finally, write III (3). The number 2,763 appears as MMDCCLXIII.
In Roman numerals, a smaller numeral before a larger numeral indicates that the smaller numeral is subtracted from the larger one. This principle is generally used for 4’s and 9’s. Thus, 4 usually appears as IV (5 minus 1). By the same rule, 9 usually appears as IX (10 minus 1). The principle is usually applied to any number beginning with 4 or 9, such as 40 (XL) and 90 (XC). However, the principle of addition can also be used in writing such numbers. For example, 400 can be written as CCCC instead of CD.
The early Roman system of about 500 B.C. differed from the system people commonly use today. For example, the Romans always wrote 4 as IIII and 9 as VIIII. In addition, they had different symbols for numbers that can be divided by 1,000. People throughout Europe used Roman numerals until the A.D. 1500’s. They found it easy to add and subtract using Roman numerals. But it was difficult to perform other calculations. In the late 1500’s, Arabic numerals began replacing Roman numerals for most uses.
See also Arabic numerals .
