# Roman Numerals

Write a function to convert from normal numbers to Roman Numerals.

The Romans were a clever bunch. They conquered most of Europe and ruled
it for hundreds of years. They invented concrete and straight roads and
even bikinis. One thing they never discovered though was the number
zero. This made writing and dating extensive histories of their exploits
slightly more challenging, but the system of numbers they came up with
is still in use today. For example the BBC uses Roman numerals to date
their programmes.

The Romans wrote numbers using letters - I, V, X, L, C, D, M. (notice
these letters have lots of straight lines and are hence easy to hack
into stone tablets).

```
 1  => I
10  => X
 7  => VII
```

There is no need to be able to convert numbers larger than about 3000.
(The Romans themselves didn't tend to go any higher)

Wikipedia says: Modern Roman numerals ... are written by expressing each
digit separately starting with the left most digit and skipping any
digit with a value of zero.

To see this in practice, consider the example of 1990.

In Roman numerals 1990 is MCMXC:

1000=M
900=CM
90=XC

2008 is written as MMVIII:

2000=MM
8=VIII

See also: http://www.novaroma.org/via_romana/numbers.html

* * * *

For installation and learning resources, refer to the
[exercism Racket page](http://exercism.io/languages/racket).

You can run the provided tests through DrRacket, or via the command line.

To run the test through DrRacket, simply open the test file and click the 'Run' button in the upper right.

To run the test from the command line, simply run the test from the exercise directory. For example, if the test suite is called `hello-world-test.rkt`, you can run the following command:

```
raco test hello-world-test.rkt
```

which will display the following:

```
raco test: (submod "hello-world-test.rkt" test)
2 success(es) 0 failure(s) 0 error(s) 2 test(s) run
0
2 tests passed
```

## Source

The Roman Numeral Kata [http://codingdojo.org/cgi-bin/index.pl?KataRomanNumerals](http://codingdojo.org/cgi-bin/index.pl?KataRomanNumerals)

## Submitting Incomplete Solutions
It's possible to submit an incomplete solution so you can see how others have completed the exercise.