/sci/ - Science & Math

[math]\mathbb{Z}_n[/math] is the set of the remainders of all natural numbers modulo [math]n[/math]
(where [math]n[/math] is an integer greater than [math]1[/math])
how is [math](\mathbb{Z}_n,+)[/math] a group when it doesn't exhibit an inverse property? thank you, i'm sorry.