An operation is commutative if the order in which numbers are listed is irrelevant when combining them for said operation. This is a bit vague without the use of examples.
Addition is commutative because
$$a + b = b + a.$$
Example:
$$4 + 7 = 7 + 4$$
because
$$4 + 7 = 11$$
and
$$7 + 4 = 11.$$
Multiplication is also commutative because
$$a \times b = b \times a.$$
Example:
$$2 \times 3 = 3 \times 2$$
because
$$3 \times 2 = 6$$
and
$$2 \times 3 = 6.$$
Subtraction and division are not commutative. If you invert which number is before and after the subtraction/division sign, you wind up with different values.
Example: \(9 - 7 = 2\) but \(7 - 9 = -2\).
Example: \(8 \div 4 = 2\) but \(4 \div 8 = \frac{1}{2}\).
Questions to think about:
1. Are there other commutative operations? What are they? Can you identify examples?
2. Think of other operations that are not commutative. What are they? Find examples of mathematical statements that demonstrate the operation is not commutative.