2 out of 3
This Sudoku, based on differences. Using the one clue number can you find the solution?
1 out of 3
The country Sixtania prints postage stamps with only three values 6 lucres, 10 lucres and 15 lucres (where the currency is in lucres).Which values cannot be made up with combinations of these postage stamps? Prove that all other values can be made up.
2 out of 3
If p is a positive integer and q is a negative integer, which of these expressions is the greatest?
2 out of 3
How many numbers do you need to remove to avoid making a perfect square?
3 out of 3
What is the sum of all the digits in all the integers from one to one million?
3 out of 3
Weekly Problem 6 - 2010
Can you find three primes such that their product is exactly five times their sum? Do you think you have found all possibilities?
3 out of 3
Use the differences to find the solution to this Sudoku.
2 out of 3
Special clue numbers related to the difference between numbers in two adjacent cells and values of the stars in the "constellation" make this a doubly interesting problem.
