Complex Problem Solving is Your Top Skill

Be ready for the Fourth Industrial Revolution!

According to the new World Economic Forum Report “The Future of Jobs” the most required skill is Complex Problem Solving together with Creativity and Critical Thinking.

Train yourself! Start with simple problems, for example, at Aplisclick, do it regularly and grow your most important skill.


Daan Roosegaarde uses technology and creative thinking to produce imaginative, earth-friendly designs and highlights the importance of the problem solving skills.

“There are no passengers on spaceship earth. We are all crew.” – Marshall McLuhan




To respond to growing demand of international users, we redirect to the new free website . All links  for extension .com are the same for extention .org  Now the site is hosted in Switzerland. Please update your links. Happy challenges at


Formula of Love

Professional dancersLove is like π – natural, irrational, and very important.” – Lisa Hoffman

Certain scientists think that love is a chemical state of mind and the formula for love is as follows:

dopamine + seratonin + oxytocin

C8H11NO2 + C10H12N2O + C43H66N12O12S2 

How many atoms  are there in the formula of love?


Mystic Number 7


Why we frequently use number 7?

Why there are seven days of week? seven deadly sins? seven wonders? . . . .

Look for the answer in the night sky or at

Why Is X The Unknown?

Terry Moore explains that the inventors of algebra were Arabic scientists. Their definition:

X = something, some undefined unknown thing = the unknown thing.

When the books were translated from Arabic to Spanish the Arabic unknown was “SH” that did not exist inSpanish. They replaced it by “X“.  It migrated to other European languages 600 years ago.

X is “X” because Spanish language does not have “SH“.

Cat, Rat, Hat, and Mat




Mary has a cat, and a rat, and a hat, and a mat.

If the cat is on the mat, and rat is in the hat, but the hat is on the mat, where is the rat?

This is a simple puzzle asked by Leslie Green, who collects dozens challenging puzzles.  The collection of Leslie Logic and Math Puzzles is presented at the website Aplusclick. It’s worth to try the challenging questions.




Selfie Math

Jim is going on a tour around the world. He has 5 tops, 4 bottoms, and 3 pairs of footwear. He wants to post a selfie everyday to show different places and his different outfits to his girl-friend Mary, who stays at home. He does not want to wear the same outfit twice. ## For how many days does he have enough clothing?


Leslie Green gives the answer : 96 days.

Can you explain why it is 96? What is logic behind?