I'm a grade one teacher who gave out some math homework last night to my students. It consisted of 9 questions to practice simple addition and subtraction. I always discourage them from using a calculator and say "Only if you need to double-check your answers!"
Anyways, one student's homework stood out in particular. It started out okay
$ 5 + 4 = 9\\ 8 + 0 = 8\\ 2 + 6 = 8\\ 7 - 6 = 1$
but suddenly the answers were all wrong
$ 3 + 1 = 3\\ 6 + 0 = 8\\ 6 + 5 = 6\\ 3 + 4 = 9\\ 1 + 1 = 1$
I thought "surely they couldn't have got all these questions wrong on purpose", and called the student to the front. I asked them all the questions they got wrong, and sure enough, they answered them correctly. So I showed them the homework asking "what happened with these five questions?"
They answered "I double-checked all my answers with a calculator like you said we could, and that's what the calculator said, so I changed my answers."
"Even the ones that are correct?" I asked. The student nodded.
Needless to say, I was stumped. I had no clue what this calculator was doing. I asked the student to bring in the calculator tomorrow.
In the meantime, does anyone know what is happening with this calculator?