I am new to using IF Formulas and i have two questions.

First: I have an existing simple subtraction formula in a cell, can i add a
IF Formula onto it. for example : In cell L13 "=M13-K13" CAN i now ADD a IF
formula on top of this simple formula???

Second Question: CAN i add color to a formula, specifically an IF formula????
Example "=IF(L13<M13) Then COLOR IS RED, IF NOT COLOR IS BLACK"
I know this is not really how IF formulas work, i am just explaining what i
need to do.

So to sum up, i need to add an IF formula on top of a subtraction formula,
AND use a COLOR FORMAT in the IF FORMULA.

Please help any way possible. Thanks