The following is a puzzle from Rational Amusements from Winter Evenings (1821) by John Jackson:
If from six ye take nine, and from nine ye take ten
(Ye youths, now the mystery explain;)
And if fifty from forty be taken, there then,
Shall just half a dozen remain.
Can you figure out what’s going on? This is not an easy one so you may take your time.
Have you figured it out? Simple arithmetic alone won’t solve this. You must apply your knowledge of math, Roman numerals, and wordplay to crack this puzzle.
Here’s the solution:
SIX – IX = S
IX – X = I
XL – L = X
There are more puzzles similar to this in the abovementioned book. If you like this kind of puzzle, then let me know and I’ll post a few more of them.