IL vs XLIX

Why IL is invalid and 49 must be written XLIX.

IL is not the standard modern canonical form for 49.

XLIX

49 in Roman numerals is XLIX.

Check in tool 49 encyclopedia page

What is wrong

Only IV, IX, XL, XC, CD, and CM are valid subtractive pairs.

Canonical form

XLIX is produced by this site’s conversion engine for 49.

Related mistakes

IIII vs IV VIIII vs IX IC vs XCIX Roman Numeral Subtractive Pairs