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Niels Henrik Abel
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Niels Henrik Abel

Niels Henrik Abel was born on August 5, 1802 in Finnoy, Norway, and died on April 16, 1829 in Froland, Norway. He proved the impossibility of algebraically solving the general fifth degree equation. Abel's life was dominated by poverty. After the death of his father, who was a Protestant minister in 1820, Abel had a responsibility to support his mother and family.

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What are the perfect squares?

Starting from zero, add the odd sequence and the answer will be a perfect square. Ex: Starting from 0, we add the first positive odd number, 1. We find the perfect square 1. Now we add the next odd number, 3. And so on. 0 + 1 = 1 1+ 3 = 4 4 + 5 = 9 9 + 7 = 16 16 + 9 = 25 25 + 11 = 36 36 + 13 = 49… * Submitted by Jorge Pereira Junior Nine tables with fingers Index Next >> What are the leap years?
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Nine tables with the fingers

This is a simple way to multiply (from 1 to 10) by 9. We should consider the fingers counting from left to right and numbering them sequentially from 1 to 10. So, just lower the finger corresponding to the number we want to multiply by 9, and we will have the result. For example: 4x9.
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Square Root of Sequential Numbers

The square root of ascending and descending sequential numbers is always equal to number 1 in the quantity expressed by the largest digit contained in that number. EXAMPLES: Guessing a Date of Birth Contents Next >> Sequential Time
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When does a century begin?

A century begins in a year 01 and ends in a year 00. For example, the twentieth century began in 1901 and ended in 2000 and the 21st century began in 2001 and will end in 2100. However, for some, they recognize the changes made. To the Gregorian calendar in 1582, a century begins in a year 00 and ends in a year 99.
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The fantastic coin trick

Take 5 coins and have one person arrange them the way they want (face or crown up). For example: See that in this example 3 crowns and 2 heads were chosen. Now turn around and ask the person to flip as many coins as he wants. Each time she turns a coin, she must say the word "I will come".
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The largest prime number of Fermat

Fermat's highest known cousin record: 167176 32768 +1, which has 171153 digits was discovered by Yves Gallot (this is the eighth largest known cousin today, and the largest known non-mersenne cousin. What are friendly numbers? Index Next >> How many decimal places of the number Pi are known?
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Superstition Around Number 13

Do you know the origin of superstition around the number 13? In Norse mythology, we find a legend on the subject. Odin, chief of an Asian tribe, established his kingdom in Scandinavia. To administer it, celebrate religious rituals, and foretell the future, Odin would have chosen twelve sages, gathering them at a banquet at the Valhalla, abode of the gods.
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Inch

The inch is an English unit of measure. It is equivalent to 2.54 centimeters or 25.4 mm. It originates in the ancient age, when the Romans measured the length with their own thumb. Thus, the inch is the width of a regular human thumb, measured at the base of the nail. In an adult human, this measurement is approximately 2.5 cm.
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Numeric characters

The numeric characters we use today have an Arabic (probably Moroccan) origin and are over a thousand years old. One possible historical explanation is that erosion from use has altered them slightly, but the original idea seems to have a curious explanation: "1" has an angle O "2" has two angles O "3" has three angles… The "0" has zero angles!
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Why do prime numbers have this name?

We currently define prime numbers as those that have only 4 divisors: + or - itself, +1 and -1. But when first thought out, most likely by Pythagoras, about 530 BC, the word prime was not related, but rather primary. The idea of ​​primary numbers, introduced by Pythagoras, continues today.
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Brazil of 100 people

According to data collected by IBGE, if Brazil were a country with 100 people, for each group of 100 people the country would have: - 18 functional illiterate people; - 16 rural workers; - 20 couples; - 51 women; - 50 people of class C; - 28 people with home phones; - 7 blacks; - 74 Catholics; - 10 graduates in any college; - 42 Southeast residents.
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Origin of the word sine

The word sine is derived from the Latin sinus meaning "bay" or "fold" from an erroneous (Arabic) translation of the Sanskrit jiva, and its variant jya. Aryabhata used the term ardha-jiva ("half-rope"), which was abbreviated to jiva and then transliterated by the Arabs as jiba. European translators such as Robert of Chester and Gherardo of Cremona in twelfth-century Toledo mistook jiba for jaib, meaning "bay," probably because jiba and jaib are written in the same way in Arabic script (this writing system in one of their form does not provide the reader with complete information about the vowels).
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Hilbert Hotel

Here at the Hotel de Hilbert, there are always vacancies! In 1925 Hilbert presented an infinity paradox that became better known as the Hilbert Hotel. There are infinite guests in this hotel and it is packed, but whenever a customer arrives the manager asks guests to jump from room to room next door.
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The humans and the numbers

If we sleep an average of 8 hours a day, at age 40 we will have slept 13 years. The skeleton of a 64-pound man weighs about 11 pounds. One person blinks about 25,000 times a day. If heart disease, cancer, and diabetes were eradicated, a man's life expectancy would be 99.2 years.
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Origin of multiplication and division signals

The sign of X, which we indicate in the multiplication, was used by the English mathematician Guilherme Oughtred in the book Clavis Matematicae, published in 1631. That same year, Harriot, to also indicate the product to be made, placed a point between the factors. By 1637 Descartes was already limited to writing the juxtaposed factors, thus abbreviating any product.
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Origin of the word calculation

Former shepherds, to control their flocks of sheep, associated them with stones that they kept in bags. Each sheep corresponded to a pebble. At the beginning and end of the day, they made the appropriate correspondences. If stone was left, sheep was missing. Since Latin in stone means "Calculus", hence the word calculus.
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Challenge 109

Relationship with Perivaldo Difficulty Level: I am a man. If Perivaldo's son is the father of my son, what is my relationship to Perivaldo? Challenge 108 The Rooms and the Lamps Challenge Index Next >> Challenge 110 The Traveler's Gold
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Challenge 126

Aligning the Points Difficulty Level: Can you align twelve points in seven rows with four points in each? Challenge 125 How many single men are there? Challenge Index Next >> Challenge 127 The Night Guard's Resignation
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Challenge 110

The Traveler's Gold Difficulty Level: A traveler had to pay for a week's stay (7 days) in a hotel, with only one gold bar to pay. The hotel owner challenged the traveler to accept the gold payment. The proposal was as follows: "I accept the gold payment.
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Challenge 13

Lady's Age Difficulty Level: - I'm twice as old as you were when I was the age of four. In five years the sum of our ages will be 82 years. If you were one of those present, would you conclude that you are how old? Challenge 12 Escalator Challenge Index Next >> Challenge 14 Wine Bottles
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