properties  basic operations
• the rules that set down particular properties
in relation to operations on numbers.
e.g. a + b = b + a
EXAMPLES:
Properties of equality
Reflexive property of equality
a = a
Symmetric property of equality
If a = b, then b = a.
Transitive property of equality
If a = b and b = c, then a = c.
Addition property of equality
If a = b, then a + c = b + c.
Subtraction property of equality
If a = b, then a – c = b – c.
Multiplication property of equality
If a = b, then a × c = b × c.
Division property of equality
If a = b and c ≠ 0, then a ÷ c = b ÷ c.
Substitution property of equality
If a = b, then b may be substituted for a
in any expression containing a.
Properties of inequality
Exactly one of the following is true:
a < b, a = b, a > b.
If a > b and b > c then a > c.
If a > b, then b < a.
If a > b, then –a < –b.
If a > b, then a ± c > b ± c.
If a > b and c > 0, then a × c > b × c.
If a > b and c < 0, then a × c < b × c.
If a > b and c > 0, then a ÷ c > b ÷ c.
If a > b and c < 0, then a ÷ c < b ÷ c.
