I have single-digit multiplications just kinda cached as ingrained associations between any two given digits and their product, but now I'm curious what algorithm you were using for them. Repeated addition maybe?
The "Phantom of Heilbronn" was an unknown female serial killer, whose DNA was found at numerous crime scenes across Austria, France and Germany from 1993 to 2009. It was eventually realised that the DNA belonged to a woman working in a factory, making the cotton swabs that were used to collect evidence.
Or this one from Brooklyn Nine Nine, that I inexplicably can't find an actual video clip of
"Ice floats, so if the glacier is free-floating, then it melting doesn’t cause a sea level rise"
A thing I recently learned: this is only true of ice floating on fresh water.
Salt water is more dense than fresh (and the ice itself is still mostly fresh even if it formed out of sea water) so ice floating on the sea floats a little higher than it would float on freshwater. This reduces its displacement and means that melting it does somewhat increase the water level.