I understand that this is a bit of offtopic but mathoverflow is my last resort, as google did not help.

I am about to publish an English translation of my Russian book for high school students. The problem is that many of our references are in Russian and not translated. So, I would be very grateful if people can recommend:

1) An introduction to group theory suitable for high-school students. Ideally it would emphasize the idea of the symmetry, discuss permutations in details and maybe prove something like Cayley's theorem in the end.

2) A book on the Fundamental Theorem of arithmetics.

3) An elementary book on Galois theory

4) Something very elementary about topology, like Mobius bundles, classification of surfaces, knots, maybe, a little bit of general topology, like Cantor set.

5) A few books for younger students, that is, books on mathematical puzzles or simpler olympiad problems.