Roman numerals greater than 1000

The rule for Roman numerals is that you cannot use more than three of the same symbol in a row. We know now that the way to remember the symbols is by remembering:

'I Value Xylophones Like Cows Do Milk'.
`I=1`,  `V=5`,  `X=10`,  `L=50`,  `C=100`,  `D=500`,  `M=1000`

But 4000 would then  = `MMMM` and you can't have more than three of the same symbol in a row.

The Romans got over this by putting a dash over any symbol to represent 1000 times the value of that symbol.

(Also note that Romans sometimes used an `M` and sometimes `bar I` but they mean the same thing).

`I` = 1

`V` = 5

`X` = 10

`L` = 50

`C` = 100

`D` = 500

`M` = 1000

`bar I` = 1000 x 1 = 1000

`bar V` = 1000 x 5 = 5,000

`bar X` = 1000 x 10 = 10,000

`bar L` = 1000 x 50 = 50,000

`bar C` = 1000 x 100 = 100,000

`bar D` = 1000 x 500 = 500,000

`bar M` = 1000 x 1000 = 1 million

The number 4000 thus becomes:

4000 = `Mbar V`

4001 = `Mbar VI` 

4002 = `Mbar VII`

4003 = `Mbar VIII`

4004 = `Mbar VIV`