Please improve these comprehensions (was meaning of [ ])

[Chris Angelico]

On Thu, Sep 7, 2017 at 5:59 PM, Marko Rauhamaa <marko at pacujo.net> wrote:
> Dennis Lee Bieber <wlfraed at ix.netcom.com>:
>
>> On Wed, 06 Sep 2017 10:37:42 +0300, Marko Rauhamaa <marko at pacujo.net>
>> declaimed the following:
>>
>>>
>>>Which reminds me of this puzzle I saw a couple of days ago:
>>>
>>>   1 + 4 = 5
>>>   2 + 5 = 12
>>>   3 + 6 = 21
>>>   8 + 11 = ?
>>>
>>>A mathematician immediately comes up with a "wrong" answer.
>>>
>>
>>       I'm coming up with "96", on the basis that the "+" is a
>> placeholder for a non-standard operation
>
> That's a mathematician's "wrong" answer. Stefan Ram's answer is the
> intended one.

Ian's answer has better justification. I'm going to support "banana".

ChrisA