You may also like

problem icon

Consecutive Numbers

An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.

problem icon

I'm Eight

Find a great variety of ways of asking questions which make 8.

problem icon

Calendar Capers

Choose any three by three square of dates on a calendar page...

Different Magic Square

Stage: 3 Short Challenge Level: Challenge Level:1

The numbers $13$, $10$ and $7$ form a diagonal, so this tells you the total of each row, column and diagonal is $13+10+7=30$. The first column then has middle cell $30 - 13 - 9 = 8$, the bottom row has middle cell $30 - 9 - 7 = 14$ and the other diagonal has top-right cell $30 - 9 - 10 = 11$.

The other two cells can then be calculated in the same way, giving the completed grid as below:


This problem is taken from the UKMT Mathematical Challenges.
View the archive of all weekly problems grouped by curriculum topic