No, they are different, here's how:

First, the phrase

*a number*means an arbitrary variable, let's call it x.

7 less than a number means we subtract 7 from x:

x - 7

A number less than 7 means we subtract x from 7:

7 - x

As you can see:

x - 7 <> 7 - x so

**they are different**