You may also like

The Mathemagician's Seven Spells

"Tell me the next two numbers in each of these seven minor spells", chanted the Mathemagician, "And the great spell will crumble away!" Can you help Anna and David break the spell?

Folding, Cutting and Punching

Exploring and predicting folding, cutting and punching holes and making spirals.

Seven Pots of Plants

There are seven pots of plants in a greenhouse. They have lost their labels. Perhaps you can help re-label them.

Marvellous Matrix

Age 7 to 11
Challenge Level

This problem was written for new year $2002$.

Circle any number in the matrix, for example, $608$ as below. Draw a line through all the squares that lie in the same row and column as your selected number.

Circle another number which has not got a line through it, for example, $343$ and again rule out all squares in the same row and column.

Repeat for a third time, then circle the remaining number which has not got a line through it.

Add all the circled numbers together. Note your answer.

Try again with a different starting number. What do you notice?

See if you can work out how this matrix works.
Below is a simpler one which might be easier to investigate.

Can you make a similar matrix which generates a different total?