Decimal Roman
Notes:
Roman numerals
The numeral system which is known as roman numbers was based on the numeral system of the Etruscans who were a sophisticated pre roman civilization located in the center of italy, the romans used this system to measure lengths and quantities. The roman numerals were used in Europe until the late middle ages at around the 14th and 15th centuries.
The roman numbers are presented by 7 latin letters I, V, X, L, C, D, and M each of them has a different value (see the table bellow). They are arranged so that if a lower value is located at the left of a highter value then the lower value is reduced from the highter value like IV is equal to
5 − 1 = 4, and if it is located at the right then it is added to the value like
VI is 5 + 1 = 6. Sometime the roman used four consecutive same symbole in order to eliminate the necessity of subtructing values like IIII insted of IV or XXXX insted of XL or CCCC insted of CD.
Clock
A clock with roman numerals
Standard numbers values Extanded values
Maximum number up to 4,999 Maximum number up to 4,999,999
Roman Decimal Roman Decimal
I 1
V 5 V     v 5000
X 10 X     x 10000
L 50 L     l 50000
C 100 C     c 100000
D 500 D     d 500000
M 1000 M     m 1000000
Table of roman numbers from decimal:       Size:
Practice the roman and decimal numerals
Jscript code to calculate decimal to roman and roman to decimal numbers
// Use this values for the regular roman numbers up to 4,999 //
var decimals = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1];
var roman = ["M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V",
"IV", "I"];
// Use this values for the extended roman numbers up to 4,999,999 //
var decimals = [1000000, 900000, 500000, 400000, 100000, 90000, 50000,
40000, 10000, 9000, 5000, 4000, 1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1];
var roman = ["m", "cm", "d", "cd", "c", "xc", "l", "xl", "x", "Mx", "v",
"Mv", "M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"];
function decimal2Roman(D) {
var R = '';
for (var i = 0; i < decimals.length; i++) {
while (D >= decimals[i]) {
R += roman[i];
D -= decimals[i];
}
}
return R;
}
function Roman2Decimal(R) {
var D = 0;
for (var i = 0; i <= decimals.length; i++) {
while (R.indexOf(roman[i]) == 0) {
D += decimals[i];
R = R.replace(roman[i], '');
}
}
return D;
}