LI (50 + 1) is the accepted form of writing 51. XLXI would represent 40 + 11 and it is a totally incorrect and unnecessarily complicated way to write 51. It would not be considered good practice to deduct 10 from a number (XL) only to add 11 (XI) to it in the same numeral.
Fifty-one (51).
51= LI in Roman Numerals
51 = LI 51 = LI LlLI
51 = LI
51 = LI
LI stands for the number 51 in Roman numerals.
51
LI
LI
51
1,000 is M. 051=51 and 51 is L (for 50) I (for 1). There is no Roman numeral for 0, so 1,051 in Roman Numerals is MLI.
It is simply LI meaning 50+1 = 51