Henry Ernest Dudeney/Modern Puzzles/59 - The Two Digits

by : $59$

 * The Two Digits
 * Write down any $2$-figure number (different figures and no $0$)
 * and then express that number by writing the same figures in reverse order,
 * with or without arithmetical signs.


 * For example, $45 = 5 \times 9$ would be correct if only the $9$ had happened to be a $4$.
 * Or $81 = \paren {1 + 8}^2$ would do, except for the fact that it introduces a third figure: the $2$.