Final answer:
According to the commutative property, 30 + 10 + 20 can be rewritten correctly as 30 + 20 + 10 = 50 + 10 = 60.
Step-by-step explanation:
The commutative property states that the order of adding numbers does not change the result. So, we can rewrite 30 + 10 + 20 as 20 + 30 + 10. Simplifying, we get 50 + 10 = 60. Therefore, the correct choice is:
30 + 20 + 10 = 50 + 10 = 60
Learn more about Commutative property of addition