1. **Problem:** Use the commutative property to show that the expressions are equal. 2. **Commutative Property of Multiplication:** This property states that for any numbers $a$ and $b$, $a \times b = b \times a$. 3. **Example:** $2 \times 3 = 3 \times 2$ which simplifies to $6 = 6$. 4. **Apply to part a:** $5 \times 10 = 10 \times 5$ 5. Calculate both sides: $5 \times 10 = 50$ and $10 \times 5 = 50$ 6. Both sides equal $50$, so $5 \times 10 = 10 \times 5$ is true. 7. **Apply to part b:** $4 \times 5 = 5 \times 4$ 8. Calculate both sides: $4 \times 5 = 20$ and $5 \times 4 = 20$ 9. Both sides equal $20$, so $4 \times 5 = 5 \times 4$ is true. 10. **Apply to part c:** $7 \times 9 = 9 \times 7$ 11. Calculate both sides: $7 \times 9 = 63$ and $9 \times 7 = 63$ 12. Both sides equal $63$, so $7 \times 9 = 9 \times 7$ is true. **Final answers:** - a. $5 \times 10 = 10 \times 5 = 50$ - b. $4 \times 5 = 5 \times 4 = 20$ - c. $7 \times 9 = 9 \times 7 = 63$