Source of this "anecdote"? Wikipedia says the following:I just want to write an anecdote about Karl F. Gauss. One day he came from school and he was probably a kid of 9 or 10 years, hanaded a letter to his mother and said
“Mother, my teacher has given me this letter and told me to hand over it to you without reading it”.
His mother opened the letter and read it (in her mind, not loud out), after reading it she remain quiet for few minutes. Gauss asked her many times about what was written in the letter, finally she replied
“Your teacher has written that you have far more ability than what the school can offer and develop, so your teacher suggested you to leave the school and work on your own great mind, develop it by your own as no one is able enough to teach you my child”
After that, Gauss became an autodidact and did many charismatic works in Matheamtics. After many years when his mother died, he was just looking for her things, suddenly in her old box he found that same letter and read it, something like this was written in it
“We are sorry Mrs. Gauss but your son Karl F. Gauss is a very stupid kid and we cannot keep him in our school anymore.”
Gauss murmured “It’s my mother who has made me what I am, It’s only because of my mother that I have reached here in my life”.
"His mother was illiterate and never recorded the date of his birth, remembering only that he had been born on a Wednesday, eight days before the Feast of the Ascension (which occurs 39 days after Easter). "
So reading a letter and being illiterate don't go well together. I hope you are not making things up.