Based on below equation logic, Can you prove that the below algebraic equation is true? 11 - 1 = 10 ?

Question

If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

Answer 1

This is meaningful only if we convert every number here into their roman number equivalents and subtract 1 by removing I from the number.
29 - 1 = 30
XXIX - I = XXX (Roman equivalent of number 30)
14 - 1 = 15
XIV - I = XV (Roman equivalent of number 15)
9 - 1 =10
IX - I = X (Roman equivalent of number 10)
Hence,
11 - 1 = 10
XI - I = X (Roman equivalent of number 10).