Like this: 0 1 2 3 4 5 6 7 8 9. They are the numerals we all use.
Hindu
The Roman numerals are XLV.
20 in Roman numerals is XX.
MCMLXXXIX
DCLXVI
Hindu
18 in roman numerals looks like XVIII
The Roman numerals are XLV.
300 would be represented by 'CCC' in roman numerals.
DCLXVI
MCMLXXXIX
XXI
VII
MMDCCCLXXXVI
MCMLII
XL
MCMLXXXV