Very often when $$$n$$$ and $$$m$$$ are variables in a problem, $$$n$$$ will appear first. Alphabetically $$$m$$$ comes first, so why is this the case? For instance when $$$p$$$ and $$$q$$$ are variables, they always seem to come in the right (alphabetical) order.
My thought is that $$$n$$$ is a very popular variable choice, and no one ever uses $$$o$$$ as a variable (easily confused with 0.) so $$$m$$$ is the next natural choice. $$$m$$$ also looks right after $$$n$$$, since it looks like two $$$n$$$'s together. I'm curious if problem setters have other reasonings.
This is the case because $$$n$$$ is the natural thing to come in mind when talking about number of items.
And m is the second natural thing to come in mind when talking about nuMbers
why not U
U are busy programming, can't waste time remembering a single value...
Even in the keyboard layout n comes before m. I don't know why m is treated so badly in the english alphabet.
Without m we are mothing.
Perhaps a few influential mathematicians decided a long time ago to use the variables of $$$n$$$ and $$$m$$$ (maybe because $$$n$$$ could stand for Number and $$$m$$$ would be the next logical choice for a letter) and then everyone just stuck with this notation.
Add also a $$$k$$$
Racism
it is because $$$n$$$ is used most often standalone, so when you need another variable with similar meaning, $$$m$$$ is the best candidate. It does not make sense to put $$$m$$$ first because it is not the one with the greatest standalone usage, so it would be confusing to have both $$$n$$$ and $$$m$$$ appearing first, when instead you could have $$$n$$$ appear first at all times.
Because someone first used it somewhere, and then everybody copied it, and then it became the standard thing everybody easily understood, like the same reason why we use 'i' and 'j' as loop counters. Nice observation tho.
This is such a letterism