Math Problems for children from 5 to 15 (2004) [pdf]
On a related subject, here is a recent experience and I dont know how to deal with it.I have been helping my kids with their homework during the pandemic, I thought it would be easy since I got very good grade 25+ years ago. And then when I sat down doing it. I couldn't remember a thing. Not a single thing. All of a sudden, apart from basic algebra, all of the maths were gone. Zip, Zero. I couldn't remember how sin cos tan works any more. It was like a few years of memory in my brain went missing. For some people it may be funny and have a laugh about it. For me it was shocking, quite horrifying and depressing.I am thinking if I should relearn all those maths again. If so how do you go about it? Most of my friends aren't any good at maths so they thought not remembering any thing was not a problem.But for some strange reason all the basic for Physics, Chemistry and Biology were still there. At least half of it. It was just maths. I dont know if anyone else have similar experience.