Nib asked, and Nib — askNib's tutor — drew the answer live at a whiteboard. This is the spoken transcript; enable JavaScript to watch it drawn.
Why can't AI count the r's in strawberry? (for a curious adult who uses chatbots but has never studied computing). Cover, in this order: What does an AI actually receive when you type a word?; Where do tokens come from?; Why is strawberry split into pieces the model can't see inside?; How does a model learn spelling at all?; Why does letting it write the letters out fix the count?; What else do tokens explain? — page 1: Numbers, Not Letters
You see ten letters, s-t-r-a-w-b-e-r-r-y. Hold that picture, because the model is about to receive something very different.
The model is arithmetic all the way down. Arithmetic needs numbers, so your words get converted into a list of numbers before anything else happens.
Imagine a catalog where every text piece has an ID number. Your message becomes just those IDs, in order. The model never sees the pieces themselves.
A number is only a label, like a phone extension. It says nothing about how a name is spelled; the letters are simply not stored inside it.
Asking about r's means asking about letters the model never received. It only gets number chunks. Next: where do those chunks come from?
Remember this: the chatbot never saw your letters, only numbers standing for pieces of text, and that is where the strawberry trouble begins.