I think it’s not true 
FT verson 2.1 (753).
Can you give the full document for context?
I think the problem must be do to some editing sequence, or do to more context in the original document. When I open your document I see:
Which I think is the correct result. Do you still see a different result when you open the document that you sent me afresh?
Thank you!!
Yes, now it’s right.
And can I see not exponential result?
Truth is I’m not sure. For the actual math part FoldingText is using http://mathjs.org. I just took a quick look and didn’t immediately see if the result representation can be controlled from the input or not. But maybe. Anyway good idea to take a look at that site anyway to learn about more advanced features such as variables and functions.