I just wrote and passed the 40-221 exam. There was one question that really bothered me. The questions was something like: Which one of the following data types could be used as a total in a report footer? The options were Integer, BigInteger, Number, and Decimal. I chose Decimal. But in reality, except for the invalid Number data type, any of these options is viable. The question was not phrased “…could NOT be used…” or else I would have chose Number. What would you have chosen?
I guess there is one important part missing in the question: “when using the TotalFields property in the dataitem…” - and that must be decimal. At least it’s not mentioned in help, but when you try to execute a report with a field different than decimal in that property it will raise an error.
Of course you can sum any “number” data type within the triggers by code…