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