## Not Knowing Math Can Cost $15,000

May 20, 2018 Leave a comment

A big number of people can lack basic math skills.

Math and Logic Puzzles

May 20, 2018 Leave a comment

A big number of people can lack basic math skills.

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May 7, 2017 Leave a comment

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 aplusclick.org

June 10, 2016 Leave a comment

The classical recreational math authors are Lewis Carroll, Henry Dudley, Martin Gardner, Sam Loyd, and Yakov Perelman.

This an example of classical math puzzles: https://www.aplusclick.org/k/5423.htm :

(10^{2} + 11^{2} + 12^{2}) – (13^{2} + 14^{2}) = ?

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

April 23, 2016 1 Comment

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?*

April 10, 2016 Leave a comment

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.”

February 3, 2016 Leave a comment

Try to solve the following problem suggested by * Leslie Green*:

*What is the difference between the number of letters in UPPER CASE and lower case in the text?*

Most of the people and me too answered the question fast: * None*.

If you give the same answer, read the question again.

The trivial advice is often useful: “Try to answer exactly to the question.”

Do you get another answer? What is it?

Another example: A shopkeeper of a Dairy stands six feet tall and wears size 13 sneakers. What does he weigh?

February 26, 2015 Leave a comment