You may also like

problem icon

I'm Eight

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

problem icon

More Mods

What is the units digit for the number 123^(456) ?

problem icon


Choose any 3 digits and make a 6 digit number by repeating the 3 digits in the same order (e.g. 594594). Explain why whatever digits you choose the number will always be divisible by 7, 11 and 13.

Producing Zeros

Stage: 3 and 4 Short Challenge Level: Challenge Level:1
You could write this problem out as 1x 3 x 4x 6 x 7 x 8 x 9 x (2 x 5) x 10. The product of the first seven numbers is not a multiple of ten, but the last part gives us 10 x 10 so the overall product must be a multiple of 100, but not a multiple of 1000. So the answer is two zeros.

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

View the previous week's solution
View the current weekly problem