If the distinction between ordinal and cardinal forms for the number 1 at some decade is by suppletion, then it is also by suppletion for the same numeral at lower decades.
Standardized
IF the distinction between ordinal and cardinal forms for the number 1 at some decade is by suppletion, THEN it is also by suppletion for the same numeral at lower decades.
E.g. French: vingt et un ‘21’ – vingt et unième ‘21st’;un ‘1’ – premier ‘1st’.