**Contents**

## Which number can make everyone stand up?

Answer: The answer to this math riddle is 21. You probably just guessed to answer this math riddle, which is fine, but you can also work it out algebraically. The two-digit number ab stands for 10a + b since the first digit represents 10s and the second represents units.

## How can you take 2 from 5 and leave 4?

What is the answer to How can you take 2 from 5 and leave 4 riddle? The answer is IV. If you remove the first and last letter from world FIVE, you are left with IV which is roman number for 4. 2.

## What is the hardest math puzzle?

For decades, a math puzzle has stumped the smartest mathematicians in the world. x3+y3+z3=k, with k being all the numbers from one to 100, is a Diophantine equation that’s sometimes known as “summing of three cubes.”

## What is the half of 2 2 riddle?

What is half of two plus two? The answer is three. 2.

## Who invented zero?

About 773 AD the mathematician Mohammed ibn-Musa al-Khowarizmi was the first to work on equations that were equal to zero (now known as algebra), though he called it ‘sifr’. By the ninth century the zero was part of the Arabic numeral system in a similar shape to the present day oval we now use.

## What has a ring but no fingers?

A lot of users have been wondering why is the answer to the riddle is the telephone. Taking the first line into consideration, “ring” here describes the sound a telephone makes when a call comes through.

## What can fly without wings?

The answer to the “what flies without wings” riddle is “time”.

## What has the neck but no head?

The answer to the “who is that with a neck and no head” riddle is “a shirt”. There you have it!

## How can you add 8 to get 1000?

## What is the hardest puzzle in the world?

In 1996, the mathematical logician George Boolos (above) published a paper describing “the hardest logic puzzle ever” which he attributed to the logician Raymond Smullyan. The puzzle has gained much attention. Here it is in all its glory: “Three gods A, B, and C are called, in some order, True, False, and Random.

## How do you solve a tricky math puzzle?

## What are some hard math problems?

**5 of the world’s toughest unsolved maths problems**

- Separatrix Separation. A pendulum in motion can either swing from side to side or turn in a continuous circle. …
- Navier–Stokes. …
- Exponents and dimensions. …
- Impossibility theorems. …
- Spin glass.

## How many 9’s are there in 100?

There are total 20 nine’s between 1 and 100. 9, 19, 29, 39, 49, 59, 69, 79, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99. you can count total 9 in these series.

## What dance has no legs?

No legs have I to dance, No lungs have I to breathe, No life have I to live or die And yet I do all three. What am I? Answer: I am a fire.

## What is 50 divided half?

Half of 50 equals 25. Since the denominator of the fraction 1/2 is a 2, this means the whole is divided into two equal parts.

## Who Discovered 1?

In category theory, 1 is sometimes used to denote the terminal object of a category. In number theory, 1 is the value of Legendre’s constant, which was introduced in 1808 by Adrien-Marie Legendre in expressing the asymptotic behavior of the prime-counting function.

## Who invented school?

Horace Mann invented school and what is today the United States’ modern school system. Horace was born in 1796 in Massachusetts and became the Secretary of Education in Massachusettes where he championed an organized and set curriculum of core knowledge for each student.

## Who Discovered number 1?

Hindu-Arabic numerals, set of 10 symbols—1, 2, 3, 4, 5, 6, 7, 8, 9, 0—that represent numbers in the decimal number system. They originated in India in the 6th or 7th century and were introduced to Europe through the writings of Middle Eastern mathematicians, especially al-Khwarizmi and al-Kindi, about the 12th century.