I like immutability as much as the next programmer, probably more. But the idea that changing the value of a variable in memory is confusing to high-school kids gets repeated way too often with way too little evidence. X isn't the x from algebra, x is your bank account balance. That it changes at payday is not a hard analogy to understand. I have yet to meet the high-school kid who thinks this says that 1=0.

Now, like the rest of us, high-school kids can get tripped up by assignment and its consequences. Functional programming offers us great tools to deal with that. But the 1=0 argument is not credible to your average procedural programmer who's been doing assignment since the age of fourteen, and is in full command of basic algebra. A much better argument would be that Haskell lets you take advantage of algebra as an analogy, and Python doesn't unless you're unusually disciplined.

Edit: removed a word for grammar.