Additive commutative law: A+B? =? b+a
Additive associative law: (? a+b？ )? +c？ =? a+(b+c)
Multiplicative commutative law: a×b? =? b×a
Law of multiplicative association: (? a×b？ )? ×c？ =? a×(b×c)
Multiplication and distribution law: (? a+b？ )? ×c？ =? a×c+b×c
Formula of the circumference of a square: c = 4a?
Square area formula: S = A2
The perimeter formula of rectangle: c = 2 (a+b)?
The area formula of rectangle: s = ab