In old-fashioned English, ‘dice’ was used only as a plural form, and the singular was die, but now ‘dice’ is used as both the singular and the plural form.
The singular usage is considered incorrect by many authorities. However, it should be noted that The New Oxford Dictionary of English, Judy Pearsall, Patrick Hanks (1998) states that “In modern standard English, the singular die (rather than dice) is uncommon. Dice is used for both the singular and the plural.”
It’s dice and die. Both are correct depending on who you ask
https://www.collinsdictionary.com/dictionary/english/dice
https://en.m.wiktionary.org/wiki/dice