Fifteen
1. It is a magic constant in a 3 x 3 magic square. This magic square was found on the back of tortoise by king Yo in China. This is the smallest non trivial magic square. An n x n magic square consists of the n2 integers from 1 to n arranged in n x n square grid, such that the sum of any row, or any column, or of one of the two diagonals, is equal to any other.
2
|
9
|
4
|
7
|
5
|
3
|
6
|
1
|
8
|
2. It is the fifth triangular number
3. It is the product of two odd primes.
15 = 3 x 5
4. It can be expressed as the sum of two consecutive numbers and interestingly it can be expressed as the difference of square of these two consecutive numbers.
15 = 8 + 7
= 82 - 72
5. The numbers of 3 digit palindromic primes are 15.
These are- 101, 131, 151, 181, 191, 313, 353, 373, 383, 727, 787, 797, 919 and 929
6. The atomic number of Phosphorus is 15.
7. It can be portioned into 176 ways.
8. It is the name of famous slide puzzle where 15 numbers are arranged in a 4 x 4 square in zig zag order and the player is required to arrange these numbers.
9. Fifteen is a solo card game in which you lay out 16 cards at a time and try to clear the deck by removing combinations that adds up to 15.
10. Fifteen squares can be arranged in a beautiful manner such that it produces 3 stars.
11. 15 and 21 are the smallest pair of triangular numbers whose sum and difference are also triangular. The next such pair is 780 and 990.
15 + 21 = 36
21 – 15 = 6
12. Fifteen is the 3rd Pentatope Number. It is a number in the 5th cell of any row of Pascal Triangle
13. 15 is the maximum number of pieces that can be produced from a cylindrical cake with four planar slices. A cake number is maximum number of regions into which a 3-dimensional cube can be partitioned by exactly n planes.
Watch the video of cutting cake at :-
(Sources :- Wikipedia)
For more information do contact
Rajesh Kumar Thakur
rkthakur1974@gmail.com
No comments:
Post a Comment