Resuming my blogging activities and unlike Dumbledore, I do not have a pensieve to review my thoughts and put them in order. On the other hand, thinking of maths problems somehow seem to make them clearer. So before I start writing long-winding blog posts, here's one I was given 16 years ago:

The length of a rectangle is 6 cm smaller than its width. If the area of the rectangle is 16, what is its perimeter?

Hint: Solvable in 5 lines or less.

Cheers,
Ali