Well it may be that I'm the Derp because what I should have done is actually ask her to calculate the sum rather than asking her to just open the calculator. She probably thought I was being condescending and she thought she'd be a smart arse.
My TV sets Siri off all the time - so annoying. I was watching the news a few months back and all of a sudden she started a google search for chemical weapons during a Syria report. I'll have the police at my door!