I'm about seven or eight years older compared to the poster (am also Romanian) and most certainly we didn't need to memorise √13, this is actually the first tim

I'm about seven or eight years older compared to the poster (am also Romanian) and most certainly we didn't need to memorise √13, this is actually the first time I hear about it. I think (and now that I've checked I'm 100% sure) that we knew by heart the first two decimals of square root of 2, meaning 1.41, and possibly Euler's number (2.71) too, even though I'm not so sure about that anymore (this was 25+ years ago).