Going from one place to another can be a difficult problem.
Have you ever wondered how your calculator or computer finds quantities such as $\sin(63^\circ)$ or $\tan(17^\circ)$?
In a recent edition of Mathematical Spectrum (the English equivalent of Parabola) the following famous problem was discussed:
Q.720 When the initial digit of a whole number $x$ is deleted, the number decreases by a factor of 13. Find all possible values of $x$.