16.4 > 16.099 >1.64 >1.6
Here, let me give you an explanation for how to this. First, you need to start with the greatest value, the tens place. Only two numbers in the set have a tens place, 16.4 and 16.099. Then since they both have the same tens place, we go to the one's place. The one's place is also the same, so we go to the tenths place. In the tenth's place, the value for 16.4 is 4 while 16.099 is 0. So we now know that 16.4 is the greatest number and 16.099 is right after it. Then we have to decide which is greater, 1.64 or 1.6. They both have the same one's place. However, for 1.6, the tenths place is 0 since there is no tenths place for it. So now we know that 1.64 is greater than 1.6.
Hope this helps!