Billy collects marbles. Each marble in his collection weighs about 4 ounces. His collection weighs about 20 pounds in all. About how many marbles are in his collection?

Billy has 80 marbles in his collection.

There are 16 ounces in a pound so we can form a equation 20 x 16 = 320
Then, we do 320 divided by 4 which gives us the figure 80. Hope this has helped you.

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.