I am wracking my brain to try and remember this toy I had when I was about 3 to 5 years old - so late 1970s. I was called something along the lines of "My First Computor" or similar. It definitely had Computor spelled like that, as I thought for many years that was the correct spelling and it was long before anyone had an actual computer!!
The best way I can describe it is a kind of plastic cash register looking thing. You would get a plastic card with a number on it, pop it into a slot and then press the keys, and the number would then "magically" appear on the top, spelled out in little yellow balls.
I'm not doing a very good job of describing it, am I? I just wanted to find a picture of it to show my kids, but can't find anything on Google! I would be so happy if anyone had any ideas!!!