Now we all know that Grandpa is a genius... but sometimes he says the most absurd things!
Today he told me:
Did you know that $6$ is prime?
$6$ is not a prime number, as it is equal to $3\times 2$. Oh wait, are you referring to the gesture your friend showed you nearly last week?
He then made one final reply before he went off to have a brownie:
No. I never said number.
What is Grandpa trying to say?
20 minutes later...
I walked up to Grandpa. Why was it taking so long for him to finish his brownie? I soon found out he fell asleep at the table.
Grandpa, wake up! I think I might know how $6$ is prime. If I am right, then you are very clever!
He suddenly jolted upwards and said:
What? You might think it's a letter? No no no no no.
And he went back to snoring. Poor Grandpa. I think it is best I leave him alone, now. $$$$ Hint 2.
I began to steal one of his brownies as he was asleep, but that was when I heard him muttering to himself. He said:
I had no idea what he meant by that, but when I looked at the brownies, they looked identical... like twins! So I just left them alone... $$$$ Hint 3. Last Hint before I will declare a 50 rep bounty.
When Grandpa woke up, I asked him:
Grandpa, what do you mean by prime?
Well, how long did I rest for exactly?
I checked my watch, and said:
Just under a full hour.
He looked baffled and made one last reply before eating the last brownie I was going to save for myself:
Well, your watch could be wrong. I slept for just over 5 minutes. That's what I mean by prime.
But I wasn't wearing it when Grandpa first asked me this ridiculous question... $$$$ Super last hint.
Well, I know the secret now! I figured it out!
No, I'm not going to tell you the answer here. I'm just going to say my watch isn't wrong... I mean, it could have been, but now I know the answer. You see, you have to pay attention to the words. Grandpa said, "No. I never said a number," and it doesn't make sense because he just did, right? The number $6$. That was why I found it so confusing...
...but he did say, "No."
Told ya my Grandpa was a genius, and now the question is: What am I trying to say?