pq = qp the commutative property of multiplication 

xy = yx the commutative property of multiplication 

qp + yx = yx + qp the commutative property of addition 

2(yx + qp) = 2yx + 2qp the distributive property 

2yx + 2qp = (2y)x + (2q)p the associative property of multiplication 
