Evolutionarily speaking, our minds are not naturally forced to remember complex mathematical equations or symbols (although it would be great if we could). “We are programmed to remember things that have real meaning, rather than just a random string of numbers,” Milstein says.
So if you frequently forget your passwords, this is actually more innate (and common) than you think. “Don’t feel bad about these things,” Milstein says. Especially when you have a million other tasks going on, random information like this is easily discarded to make room for more important things.
However, “if something we’re learning has meaning, and if it has some emotional element (funny, it’s scary, etc.), it’s more likely to remain consistent,” Milstein notes. This is why you might remember every second of the last scary movie you watched but mistype your best friend’s phone number.
So, if you want to remember something simple (say, a string of numbers like a date or phone number), mentally associate it with something silly or scary, Milstein suggests. “This is how you make those memories lasting,” he notes. Acting or using numbers in a silly sentence can help you way more than you think.