Associative Law of Addition

Theorem
On all the number systems:


 * natural numbers $\N$
 * integers $\Z$
 * rational numbers $\Q$
 * real numbers $\R$
 * complex numbers $\C$

the operation of addition is associative:


 * $a + \paren {b + c} = \paren {a + b} + c$

Proof
This is demonstrated in these pages:


 * Natural Number Addition is Associative
 * Integer Addition is Associative
 * Rational Addition is Associative
 * Real Addition is Associative
 * Complex Addition is Associative