Brainaire or Billionaire

Being a brainaire makes you feel probably better than just being a billionaire, isn’t it?

You can earn billions brain coins at Brainaire website that is full of logic brainteasers and funny questions. It is free and everything depends on your intelligence and your persistence. Give it a try at . You will not regret.

This is a sample question for a Brainiare:

What is the largest of the four options?



Chance for a Would-be Bride

girl-straws There was a tradition in old Russia. A would-be bride gathers six long pieces of straw and grasp them in her hand. She then randomly ties pairs of knots on the top and the bottom. Since there are six blades of grass sticking out above and below the hand, she will tie three knots on the top and three knots on the bottom. If she forms one big ring, she gets married soon.

Estimate the probability that the girl will get married soon.

The problem is mentioned in The New York Times NUMBERPLAY and it is credited to Sunil Singh.


Secret Agent 007

Seven secret agents are on payroll of a government.

Secret agent 001 spies on a secret agent who spies on secret agent 002,

who spies on a secret agent who spies on secret agent 003,

who spies on . . . spies on secret agent 007

who spies on a secret agent who spies on secret agent 001.  

Who spies on secret agent 007?




18 Best Aplusclick Puzzles of 2018

New challenges:

What is the easiest way to make it correct?            Answer


In what Olympic sport does the winner cross the line facing backwards?      Answer


What time is it?         Answer


What is the necessary mirror size?     Answer


Find all 18 best puzzles at

Is Zero Your Hero?

Everybody has a favorite number.  What number is your hero?

Not Knowing Math Can Cost $15,000


A big number of people can lack basic math skills.

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

Classics of Recreational Math

The classical recreational math authors are Lewis Carroll,  Henry DudleyMartin GardnerSam Loyd, and Yakov Perelman.

This an example of classical math puzzles: :

(102 + 112 + 122) – (132 + 142) = ?

The picture “Mental Count” of Russian painter Nikolay Bogdanov-Belsky contains the simple calculation. Image source : Wikipedia



The logic puzzle almost everyone gets wrong

This is a very famous logic problem:

“Jack is looking at Anne, but Anne is looking at George. Jack is married, but George is not. Is a married person looking at an unmarried person?

  • A: Yes
  • B: No
  • C: Cannot be determined”


According to the Keith E. Stanovich in Scientific American more than 80 percent of people choose C, which is not the correct answer. The correct answer is A. Why?

This is another example of a similar problem:

There are only two handshakes in a meeting: John shakes hands with a person, this person shakes hands with Anna. Does a man shake hands with a woman in the meeting?


Extraordinary Math Teaching by Dan Finkel

Dan Finkel suggested principles of extraordinary math teaching:

Math can the best of time or the worst of time.



1) Start with a question.

2) Thinking happens only when you have time to struggle.

3) (Teacher), you are not the answer key.

4) Say yes to your students’ ideas.

5) Play!

A marvelous quotation is attributed to the most brilliant scientist of the modern age, Albert Einstein: “Play is the highest form of research.”