On: Which countries are mentioned the most on Hacker N...

[obelisk_]

Is this the book? https://books.google.com/books/about/Elementary_mathematics....

[odovdor → obelisk_]

Your link points to some math review book by the same author.

I believe the author meant the drillbook such as https://issuu.com/normagee/docs/scanavi_sbornik_konkursnih_z....