Give me an expression of nine less than a number

So if you want it to be 9 less than your number (x) then you would subtract nine.

So it would be:

x - 9.

So if your "number" is 12 then you would substitute x for 12 and it would be 12-9. The answer is 3. So 3 is 9 less than a number (12).

I believe