15/03/2013 - Alpha-numbers (*)

This puzzle is rated 2 star (easy).

Description

Write out the numbers 1 to 20 (inclusive) in order, as words.

Puzzle
When placing these numbers in alphabetical order, how many numbers remain in their original position?

Check the solutions page for the correct answer.

13/03/2013 - Old News (***)

This puzzle is rated 3 star (hard)

Description

A newspaper is printed on 8 large sheets of paper that are laid on top of each other and folded in half. 

This means that the newspaper has 32 pages altogether.
The first sheet contains pages 1, 2, 31 and 32.

Puzzle
I pick up a sheet containing page 25. What are the other pages that this sheet contains?

Check the solutions page for the correct answer.

12/03/2013 - How Many Triangles 3 (**)

This puzzle is rated 2 star (medium).

Description

Make sure you can clearly see the image shown above.

Puzzle
How many triangles are there in the shape shown above?

Check the solutions page for the correct answer.

07/03/2013 - True Number (**)

This puzzle is rated 2 star (medium).

Description

I am thinking of a 6-digit number. The sum of the digits is 43. 

And only two of the following three statements about the number are true: 

1. It's a square number,
2. It's a cube number, and
3. The number is under 500000.

Puzzle
What is the number?

Check the solutions page for the correct answer.

06/03/2013 - Four 4s (10-19) (**)

This puzzle is rated 2 star (medium).

Description

During this puzzle you can only use the following mathematical functions:

• Addition
• Subtraction
• Multiplication
• Division
• Decimal point
• Square-root
• Brackets
• Power (e.g. 4 to the power 4 is 4 x 4 x 4 x 4 = 256)
• The number of 4 exactlyf 4 times.
  

Puzzle
Using only the mathematical functions and the number 4 (EXACTLY 4 times) construct the numbers from 10 to 19.

Check the solutions page for the correct answer.