Editing Subtraction (section)

==Properties==
===Anti-commutativity===
Subtraction is [[anti-commutative]], meaning that if one reverses the terms in a difference left-to-right, the result is the negative of the original result. Symbolically, if ''a'' and ''b'' are any two numbers, then
:''a'' − ''b'' = −(''b'' − ''a)''.

===Non-associativity===
Subtraction is [[associativity|non-associative]], which comes up when one tries to define repeated subtraction. In general, the expression
:"''a'' − ''b'' − ''c''"
can be defined to mean either (''a'' − ''b'') − ''c'' or ''a'' − (''b'' − ''c''), but these two possibilities lead to different answers. To resolve this issue, one must establish an [[order of operations]], with different orders yielding different results.

===Predecessor===
In the context of integers, subtraction of [[1 (number)|one]] also plays a special role: for any integer ''a'', the integer {{nowrap|(''a'' − 1)}} is the largest integer less than ''a'', also known as the predecessor of ''a''.