13. Transitive
Equality:
If a = b and b = c, then a = c
Inequality:
If a > b and b > c, then a > c
If a < b and b < c, then a < c
14. Addition
Equality:
If a = b, then a + c = b + c
Inequality:
If a < b, then a + c < b + c
If a > b, then a + c > b + c
15. Subtraction
Equality:
If a = b, then a – c = b – c
Inequality:
If a < b, then a – c < b – c
If a > b, then a –c > b – c
16. Multiplication
Equality:
If a = b, then ac = bc
Inequality:
If a < b and c > 0, then ac < bc
If a < b and c < 0, then ac > bc
If a > b and c > 0, then ac > bc
If a > b and c < 0, then ac < bc
17. Division
Equality:
If a = b and c does not equal to 0, then a/c = b/c
Inequality:
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