Linked from
The 12 pages that link to Commutative property, each with the reason it gives.
Vector additionRelated: Exchanging the addends leaves their vector sum unchanged.
AdditionRelated: It explains why the addends can switch places without changing their sum.
Abelian groupRelated: It is the defining extra condition imposed on a group operation.
ReciprocalRelated: Commutativity lets x·(1/x) equal (1/x)·x.
Product (mathematics)Related: For ordinary numbers, swapping factors leaves their product unchanged.