Can't add innerText values?

[broadvision123]

Hello,
My innerText values are concatenating instead of added. Any ideas?

Thanks!

var txtQtyBox = document.getElementById("txtPrinterQuantity2");
var lblPriceBox = document.getElementById("lblPrinterAmount2");	
var lblPriceBoxb = document.getElementById("lblPrinterAmount2b");
var lblPriceBoxc = document.getElementById("lblPrinterAmount2c");

OOTotal += (txtQtyBox.value * (lblPriceBox.innerText+lblPriceBoxb.innerText+lblPriceBoxc.innerText));