Which operations are commutative and associative?

Step-by-step explanation:

if there are two numbers a and b. then

1. a+b=b+a, commutative under addition.

2. ab=ba, commutative under multiplication.

If there are three numbers a, b, c then

1. a + (b+c) = (a+b) + c, associative under addition.

2.

a * (b*c) = (a*b) * c, associative under multiplication.