A numeric cell without formulas when entering a range of 1-12 produces a date or 44531

Vlad54k1 The number 44531 is the number that Excel uses for the date 1 December 2021. That is, day number 44531 counting from 1 January 1900. When you enter "1-12" (without the quotes) Excel interprets it as day 1 and month 12  in the current year (being 2021).

If you want to enter a text like "1-12" you can put an apostrophe in front or format the cells(s) as Text before you enter "1-12".