I was saying generally. I don't work in maths. PhD students do lots of other things than research. If we ask a PhD student to just solve these kinds of problems and nothing else, the student would do it without much difficulty.

I guess it's different in somewhere like Europe. But in Canada, most of the PhD students are paid for doing TAships, not primarily through grant. Average salary is 25k/year. Take 6-10k out for tuition, that's 15-19k/year. You get a student doing so many things for less pay. I guess, if your job only requires research then you can do it.