Roman numerals were the number system used in the Roman Empire until its fall in 300 A.D. After that, Arabic numerals were eventually adopted which is what is most commonly used today. This system proved superior in many ways, one of them being the introduction of zero, which did not exist in Roman numerals. Today, Roman numerals are used only in limited ways.

### The Use of Roman Numerals Today

Roman numerals (also sometimes called Latin numerals) have not been used in mathematics for more than 1,000 years but are still regularly used today in certain contexts such as list numbers, numbers on the clock and page numbers in a book. Other uses for Roman numerals are names of monarchs and popes (for instance "Queen Elisabeth II" and Pope Benedict VII), sequels of movies, books and video games and recurring events (XXIII Olympic Winter Games). The Roman numerals names used today are derived from those used in ancient Rome with some changes made during the Middle Ages in Europe.

### Writing Numbers in Roman Numerals

In ancient Rome, letters were used to represent the numbers. Today, Roman numerals may be written in capital or lowercase letters. Single letter symbols are used to represent the numbers 1, 5, 10, 50, 100, 500 and 1,000, as follows:

1 - I

5 - V

10 - X

50 - L

100 - C

500 - D

1,000 - M

Other numbers are represented using some combination of these. The numbers from 1 to 10 in Roman numerals are I, II, III, IV, V, VI, VII, VIII, IX, V. These are easy to memorize and are something that most people know by heart. Try, however, memorizing numbers like MMXVIII which stands for 2018, or DXLVII which stands for 547.

The good news is there is no need to memorize them at all as there is a system to all of this. Besides knowing the symbols for the basic numbers listed above, you need to remember the following two rules.

If a symbol is immediately followed by another one that has a greater value, then the value of the first symbol is subtracted from the second. For instance, IV (a combination of I and V) represents the number 4, and XL stands for 40). If a symbol is followed by another one that has an equal or lesser value, then the values of the two symbols are added. For instance, VI stands for 6 and CLI stands for 151.

### Writing 1 Million in Roman Numerals

The basic single letter symbols represent numbers up to 1,000 but don't go beyond that. So how do you write 1 million in Roman numerals?

To do that, you just need to remember another handy rule. Specifically, drawing a horizontal bar over the symbol multiplies it by 1,000. So X̅ would equal 10,000 and ̅V would equal 5,000.

So to write 1 million in roman numerals you’d have to simply write the symbol for 1,000 with a bar over it, namely ̅M.

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