Copyright © University of Cambridge. All rights reserved.

See all short problems arranged by curriculum topic in the short problems collection

What is the sum of the digits of the largest 4-digit palindromic number which is divisible by 15? [Palindromic numbers read the same backwards and forwards, e.g. 7227 or 10101.]

If you liked this problem, here is an NRICH task that challenges you to use similar mathematical ideas.

*This problem is taken from the UKMT Mathematical Challenges.*