You have (hopefully) learnt a little bit at school about geometric series, and have studied so-called 'limiting sums' of geometric series.
Issue 2
Common sense tells us that either two things happen at the same time or they do not.
Issue 3
In the last issue of Parabola George Szekeres (see the end of his article on Carmichael numbers) stated that one of the most famous problems in mathematics, Fermat's last theorem, appeared to have been solved.