Trevor is planting rows of trees on his property. he bought 16 orange trees, 8 apple trees, 24 pear trees, and 12 plum trees. he wants to plant the same number of trees in each row. each row will only have one type of tree. what is the greatest number of trees he can plant in each row?

To find the greatest common factor of all these numbers, you can list all their factors like this:

16 = 1, 2, 4, 8, 16
8 = 1, 2, 4, 8
24 = 1, 2, 3, 4, 6, 8, 12, 24
12 = 1, 2, 3, 4, 6, 12

You can see that ever number on this list is divisible by one. Looking higher, you can see that every number is divisible by two. Finally, if you look two steps higher, you know that all of these numbers have the factor of 4.

So, Trevor can plant rows of 4s.