Primes That Do Not Generate Primes When Any Single Digit Is Prepended

Giving a quick inspection at the list of prime numbers, you’d notice that 2 is the first prime number. However, prepending any single decimal digit to it would not produce other primes, that is, 12, 22, 32, 42, 52, 62, 72, 82 and 92 are composite numbers. Likewise, the third prime number, 5, also shares […]

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Pun Of The Weak: Here’s Looking At Euclid

Higgledy-piggledy Euclid Geometer Pained by the asking of “What is the use Studying the doctrines so Axiomatical?” Answered acutely, “Oh, Don’t be obtuse!” — Anthony Harrington

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Full Circle

Place 24 pigs in these sties so that, no matter how many times one circles the sties, he always find that the number in each sty is closer to 10 than the number in the previous one.

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A Zero Vector’s Woe

Here is an offbeat poem which was written by Eileen Tupaz, a then student of Ateneo University (Philippines): i’m tired of being a zero vector i’m tired of being a zero vector with no direction no dimension and no magnitude; what i need is another element — but that would be a contradiction of my […]

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The First Odd Number In The Dictionary

Suppose that each number from 1 to 10,000,000,000 written in English and then alphabetically arranged (as in a dictionary) while ignoring spaces and hyphens. What would be the first odd number in the list?

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Curious Number Substrings

If you add all the substrings of 891, the sum is 198, which is the reverse of 891: 891 → 8 + 9 + 1 + 89 + 91 = 198 This is the only 3-digit number that has this property. There is also one 4-digit number with the same property. Can you find this […]

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Gleanings From The Past #55

The Sword and the Pen The sword of the warrior was taken down for the purpose of being polished. It had not been long out of use. The rust was rubbed off, but there were spots that would not go; they were of blood. The sword was placed on the table, near the pen of […]

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A Hecatomb Of Oxen Or: Pythagoras’s Sacrifice

“Pythagoreans Celebrate the Sunrise” by Fyodor Bronnikov 1869 Legend has it that when the Greek philosopher Pythagoras discovered the Pythagorean theorem (the famous right-triangle theorem you probably first heard in algebra class then never heard it again until now), he celebrated by sacrificing a hecatomb (100 heads) of oxen to the gods. This event was […]

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Pun Of The Weak: Mathematical Feud

Two mathematicians arguing about even numbers were at odds. One of them was an exponent of his own powers and other just used strange expressions. As the arguments continued, they became irrational. Those who witnessed their negative attitudes were nonplussed. Finally, they came to an agreement due to some prime factors.

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