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There was a question in a mental math test and it expected me to calculate the first 9 terms of the following Fibonacci sequence (Note that this is how the problem was exactly given.):

The sum of the first nine terms of the Fibonacci sequence 4,7,11,18,29... is

How could I have done this in under 15 seconds? I know that if there are n terms, then $2F_n+F_{n-1}=$ Sum of $n$ Fibonacci numbers. But even this is too tedious for me.