Roman numerals are symbols that stand for numbers. They are written using seven basic symbols: I (1), V (5), × (10), L (50), C (100), D (500), and M (1,000). Sometimes a bar is place over a numeral to multiply it by 1,000. A smaller numeral appearing before a larger numeral indicates that the smaller numeral is subtracted from the larger one. This notation is generally used for 4s and 9s; for example, 4 is written IV, 9 is IX, 40 is XL, and 90 is XC.