I remember when I was a kid, Kangaroo math puzzles were incredibly fun. I don't know if you can get your hands on some materials, but they were such a blast. ht

I remember when I was a kid, Kangaroo math puzzles were incredibly fun. I don't know if you can get your hands on some materials, but they were such a blast. https://mathkangaroo.org/mks/ https://mathkangaroo.org/mks/ I recommend getting some math olympiad books; at that level they're just like puzzles so should be fun. https://artofproblemsolving.com/wiki/index.php/Olympiad_books https://artofproblemsolving.com/wiki/index.php/Olympiad_book... Go for general problem books (non-topic-specific), and start with the easiest problems that they find fun. I remember the following two books were interesting (though might be somewhat harder). You might find them on the internet archive or pdf's online. Challenging Mathematical Problems With Elementary Solutions (Volume I, Combinatorial Analysis and Probability Theory) - A. M. Yaglom, I. M. Yaglom. Challenging Mathematical Problems With Elementary Solutions (Volume II, Problem From Various Branches of Mathematics) - A. M. Yaglom, I. M. Yaglom. Additionally, look into various olympiads: American AMC 8 and AMC 10 from various years should be easiest: https://artofproblemsolving.com/wiki/index.php/AMC_Problems_and_Solutions https://artofproblemsolving.com/wiki/index.php/AMC_Problems_... And when they feel adventurous, take a look at contests. Some countries (e.g. Romania, Russia) have contests for lower grades, though they are still quite difficult. https://artofproblemsolving.com/community/c3754998_aops_yearly_contest_collections https://artofproblemsolving.com/community/c3754998_aops_year...