wierd math problem

It could be that I was just up too late and I'm not seeing something really obvious, but I having a weird math problem. in my script I have a function which calculates a discount for the purchase of tickets to a chamber music festival. Here's the function which performs as expected:

// if the patron orders tickets for 4 main events // he/she receives a 10% discount on those events function getDiscount() { $discResult = mysql_query ("select * from cart inner join items on cart.itemId = items.itemId where cart.cookieId = '" . GetCartId() . "' and items.itemDisc <> 'xx' group by items.itemDisc"); $disCount = mysql_num_rows ( $discResult ); if ($disCount >= 4) {

	             $discPrices = mysql_query ("select * from cart
		                                     inner join items
		                                     on cart.itemId = items.itemId
		                                     where cart.cookieId = '" . GetCartId() . "'
		                                     and items.itemDisc <> 'xx'");

while ($row = mysql_fetch_array($discPrices)) $reduceBy += (($row["qty"] * $row["itemPrice"]) * 0.1);

	                     echo number_format($reduceBy, 2);

	                                  }

else { $reduceBy = 0; echo number_format($reduceBy, 2); } }

When I call the function on the page to show the discount, everything is ok:

Subscriber Discount: $<?php echo getDiscount(); ?>

This displays "Subscriber Discount: $85.40" I have a variable ($totalCost) which tallies the non-discounted total cost for all the tickets purchased. ($totalCost += ($row["qty"] * $row["itemPrice"]);) which works fine. I call that variable on the page like this:

Order Subtotal: $<?php echo number_format(($totalCost), 2); ?>

Which displays "Order Subtotal: $854.00" Now here's the part that is screwy. When I try and calculate the discounted total price, using this:

$myPrice = $totalCost-getDiscount(); echo ($myPrice);

I get "8.54854" which is simply the result of the function getDiscount followed by the variable $totalCost. Of course I expected to get the result of the equation "854 - 85.40" or "768.60" What am I doing wrong? Mark -- mark hurty | mark@hurty.com | 309.764.0911