In my experience one sees roughly similar results with:

"Write a function which counts the number of a's in the input string."

"We will give you an array of words. Print out each word which appears more than 3 times in the array."

"We will give you two arrays of words. Print out each word which is in exactly one of the arrays."

It's not just the mod operator. These are toy problems for difficulty but they're not "implement the rules to a children's game"; with a few seconds of effort you can describe a boringly plausible business reason for having to implement them during a fairly pedestrian career.