How to use Format-number function with if else condition in rtf

If User want to show in two different columns, Debit and credit columns then 

Debit column will be :

 <?if: CD_TRX_AMOUNT>=0?>

<?format-number(CD_TRX_AMOUNT,"### ,###.00")?>

<?end if?>

<?if: CD_TRX_AMOUNT<0?>

<?''?>

<?end if?>

Credit column will be:

<?if: CD_TRX_AMOUNT<0?>

<?format-number(CD_TRX_AMOUNT,"-### ,###.00")?>

<?end if?>

<?if: CD_TRX_AMOUNT>=0?>

<?''?>

<?end if?>

If in same column then 

<?if: CF_TOTAL>=0?>
<?format-number(CF_TOTAL,"### ,###.00")?>
<?end if?>
<?if: CF_TOTAL<0?>
<?format-number(CF_TOTAL,"-### ,###.00")?>
<?end if?>