I thought the description Dr. Powell gave was reasonably clear:
"I wrote them down on pieces of paper after generating them and then I put them in the stack, face down, and handed them to the therapist. And she picked them up one by one,"... there's more, but no need for me to paste it here. If you want the rest, listen to the podcast or read the transcript.
Right, and one of the reasons I know it is [telepathic] not… doing this because she is a mathematical savant is based on a couple of errors that the therapist made. The therapist isn’t someone who knows math. So the therapist, when she looked at the piece of paper that had the equation that was asking for the cube roots, and this happened on two of the occasions… she is mistook the cube root symbol for meaning divide by three. So she asks the girl, “What’s the first number?” then she gives this long number and then she says and what is it divided by, and the girl says three, and then she asks, “And what’s the answer?” and the girl gives the answer for the cube root, she doesn’t give the answer for dividing that number by three.