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Mathematics

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24 likes 7.0
(Challenging)
The Famous Hole in a Sphere in Mathematics
This incredible problem was first made famous by Martin Gardner with his 'Mathematical ...
Added over 2 years ago by Valentin currently with 49 comments
7 likes 6.6
(Challenging)
Find the Missing Number in Mathematics
In this table, each row across follows the same pattern of numbers. See if you can disc...
Added about 1 year ago by copter currently with 15 comments
4 likes 6.4
(Challenging)
Number Sequence in Mathematics
What number comes next in this sequence? 1 8 70 627 5639
Added about 1 year ago by jaX currently with 13 comments
10 likes 6.3
(Challenging)
Birthday Problem (Classic) in Mathematics
A classic problem. How many people do you need to have in a room so that the probabi...
Added about 1 year ago by Dusty currently with 20 comments
16 likes 6.2
(Challenging)
Simple 24 in Mathematics
Why is that if p is a prime number bigger than 3, then p^2-1 is always divisible by 24 ...
Added about 1 year ago by dani3l currently with 39 comments
12 likes 6.2
(Challenging)
Lockers in Mathematics
A high school has a strange principal. On the first day, he has his students perform an...
Added about 1 year ago by copter currently with 38 comments
15 likes 6.0
(Challenging)
Greatest Area in Mathematics
A farmer challenges an engineer, a physicist, and a mathematician to fence off the larg...
Added about 1 year ago by johnp currently with 33 comments
10 likes 6.0
(Challenging)
Farmer's Market in Mathematics
You're a farmer. You're going to a market to buy some animals. On the market there are ...
Added about 1 year ago by jaX currently with 40 comments
16 likes 5.9
(Moderate)
Mutilated Chessboard Problem in Mathematics
Suppose a standard 8x8 chessboard has two diagonally opposite corners removed, leaving ...
Added about 1 year ago by copter currently with 24 comments
7 likes 5.8
(Moderate)
All Apples in Mathematics
On the market, mrs. Jones and mrs. Smith sell apples. Mrs. Jones sells her apples per t...
Added about 1 year ago by copter currently with 19 comments
4 likes 5.8
(Moderate)
The Four Sevens in Mathematics
(5 + 5) x (5 + 5) = 100 Four 5's written with simple arithmetical signs can be arran...
Added about 1 year ago by dani3l currently with 22 comments
12 likes 5.5
(Moderate)
Divide 1 to 20 in Mathematics
What is the smallest whole number that can be divided by any number from 1 to 20 (inclu...
Added about 1 year ago by Dusty currently with 25 comments
13 likes 5.4
(Moderate)
Cutting Numbers in Mathematics
When is Seven half of Twelve?
Added about 1 year ago by Tsion currently with 45 comments
5 likes 5.0
(Moderate)
I enjoy Random Walks on the Beach in Mathematics
There is a MxN grid (see picture) of spots. You start from the top left spot and go to...
Added 9 months ago by kash currently with 34 comments
7 likes 4.9
(Moderate)
Don't Hang Yourself in Mathematics
A fool wants to tie a rope around the earth. So he buys a rope of 40,000 KM and ties it...
Added about 1 year ago by copter currently with 30 comments