Volume 23
, Issue 3

1987

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 $x$.
 

Q.708 A four digit number $abcd$ has the property that $a+b = c\times d$ and also $a\times b = c+d$. Find all possibilities.