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

18 Aplusclick Puzzles 2018 from Igor Kokcharov, Ph.D, PMP

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Interesting Maths Facts

 

• Notches (cuts or indentation) on animal bones prove that humans have been doing mathematics since around 30,000 BC.
• Ancient Greeks used little rocks to represent numbers. The name of Calculus means pebbles in Greek.
• The = sign (“equals sign”) was invented by 16th Century Welsh mathematician Robert Recorde, who was fed up with writing “is equal to” in his equations.
• The word hundred is derived from the word “hundrath”, which actually means 120 and not 100.
• Zero (0) is the only number which cannot be represented by Roman numerals.
• Many Chinese hospitals do not have a 4th floor  because the words four in Japanese, Cantonese, Mandarin and Korean (shi, sei, si, sa) sound the same as the words in those languages for death.
• Forty is the only number with letters in alphabetical order, while one is the only one with letters in reverse order.
• The number 5 is pronounced as ‘Ha‘ in Thai language. 555 is also used by some as slang for ‘HaHaHa’.
• Zero is an even number. Mathematicians remember it. Many people take longer to decide whether it is even or odd.

17 Best Puzzles of 2017

 

Aplusclcik team chose 17 Best Puzzles of 2017.

They are:

What country has the lowest birth rate in the World?

If certain words in this question are spelt wrong, how many of the eighteen words are spelt wrong?

A claustrophobic gentleman chooses his place in the train that will enter a tunnel just after the station. Where is the best place for him?

Read more at

17 Best Aplusclick Puzzles of 2017 from Igor Kokcharov, Ph.D, PMP

Pythagorean Triples Were Known 1,000 Years Before Pythagoras

The Babylonian clay tablet from the collection of Columbia University dating from 1,000 years before Pythagoras’s theorem is a trigonometric table which has 15 pairs of numbers forming Pythagorean triples: three whole numbers a, b and c:

a² + b² = c²

The tabet is known as the world’s oldest trig table. Babylonians used the base-60 numbers, which permitted many more accurate fractions than the contemporary base 10. For example, 2/3 = 0.6666… (or 40 minutes) was a finite number. The base-60 system were inspired from such shapes as a circle and the regular hexagon (see an example).

Formula of Love

“Love 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?

Answer

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 aplusclick.org

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.