How can i explain to a friend how to compare numbers using place value

Using place value to compare numbers means adding placeholders to make each number the same length. You always use 0.
For example:
2.4
2.36
3.901
5.6533
2.01

You would add zeros so they look like this:
2.4000
2.3600
3.9010
5.6533
2.0100

Now you can compare them as they are all the same length.
So the answer is:
2.01
2.36
2.4
3.901
5.6533