InfoPath Dev

I am trying to write the formula for a text box field in my form. The formula is based on values that get inserted into a repeating table. 

The formula that I want to get working is the following 

sum (colA * colB)  where colA and colB are fields that get added to the repeating table as each row gets added. 

The error that I get with this formula is "Argument 1 must return a node-set."  Does anyone know a trick to get around this? 

Thanks

put a third field colC into your repeating table. use this function to get the value for colA * colB: number(colA) * number (colB). then on the field you wanna have the sum use sum(number(colC)). does this work ?

Hello,

You can do this by using the following formula.

sum(eval(Product, "my:value"))

Where:

Product is the repeating table name and my:value is the field value that you whant to calculate.

I've attached a form template with this example.