ActionScript 3.0 :: Adding Numbers From Input Boxes?

I'm stumped on this problem and can't seem to figure it out. Any suggestions would be welcomed. Basically I'm building a large calculator that adds over 100 input boxes. I've got it working except for the fact that if a user misses inputing a number into one of the input boxes it does not work anymore. I've tired lots of things to no avail. I just want to add the input boxes and skip those where the user did not enter any information (does not apply to them)

Here is my code.

on (press){
ReceptionTotal = Number(LocationFee) + Number(Caterer) + Number(ToastingGlasses) + Number(SecurityFee) + Number(BarPackage) + Number(WeddingCake) + Number(FoodHors) + Number(Baker) + Number(BartentingFee) + Number(CakeKnife) + Number(Servers) + Number(Flatware) + Number(Dinnerwear) + Number(Flatware) + Number(TableLinens) + Number(ChairsCovers) + Number(Glasswear) + Number(Tent) + Number(Napkins) + Number(Childcare) + Number(DanceFloor) + Number(ServingStaff) + Number(Lanterns) + Number(Heaters) + Number(Restrooms);
}

each input box has a variable name assigned to it as indicated above. I've tired setting the variables to 0, tried if statements don't know how to skip one of the above variables when no number is entered.