Equality
What property is "if 3g+4g = 12g-5g, then 12g-5g = 3g+4g"?
Symmetric property
What property is "if 2×12 = 8×3, then 2×12 = 48÷2"?
Transitive property
What property is "if 65-20 = 9×5, then (65-20)-12 = (9×5)-12"?
Substitution property