Vincent needs 30 inches of lumber to make 1 shelf . How many feet of lumber does Vincent need to make 6 shelves?

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.