It simply means to put them in order from 2 to 3
You could change all of them to 20ths to put them in order but since they all begin with 2 lets do it differently. Think of each fraction as a test score.
It is obvious that the person who got 3 out of 20 did the worst so 3/20 is lowest
9 out of 20 is a little less than 1/2 the test right so it comes 2nd
No other score is less than 1/2 So 1/2 comes 3rd
11 out of 20 is just a little better than 1/2 so it comes 4th
Finally 4 out of 5 is the best score so it comes 5th
Here is the order from 2 to 3
2 2 3/20 2 9/20 2 1/2 2 11/20 2 4/5 3
Now for the decimals
Let's put them one above the other to start and add zeros to make them all the same length:
2.500
2.125
2.375
2.875
It easy to see now that the order from least to greatest is:
2 2.125 2.375 2.5(00) 2.875 3
The directions to put them on a horizontal number line means simply to draw a line that passes through each of the answers above. See my document to see a skeleton of what it might look like.