Do the phrases 7 less than a number and a number less than 7 mean the same thing explain

Do the phrases 7 less than a number and a number less than 7 mean the same thing explain

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