George is building a fence. He builds his fence at a constant rate of \frac{1}{3} 3 1 section of fence every \frac{1}{2} 2 1 hour. At this rate, what fraction represents the section of fence George can build per hour?

This law is sometimes called the grouping property. as you can see, regardless of how the numbers are grouped, the answer is still 13. the associative law of multiplication is similar to the same law for addition. it says that no matter how you group numbers you are multiplying together, you will get the same answer.