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Mathematics

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24 likes 7.2
(Challenging)
The Famous Hole in a Sphere in Mathematics
This incredible problem was first made famous by Martin Gardner with his 'Mathematical ...
Added about 1 year ago by Valentin currently with 16 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 0 comments
12 likes 6.5
(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 2 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 0 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 6 months ago by Dusty currently with 0 comments
14 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 4 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 3 comments
9 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 10 months ago by jaX currently with 4 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 4 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 10 months ago by copter currently with 0 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 4 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 6 months ago by Dusty currently with 4 comments
13 likes 5.4
(Moderate)
Cutting Numbers in Mathematics
When is Seven half of Twelve?
Added 10 months ago by Tsion currently with 5 comments
4 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 3 months ago by kash currently with 3 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 3 comments