Follow the clues to find the mystery number.
What do the digits in the number fifteen add up to? How many other numbers have digits with the same total but no zeros?
A church hymn book contains 700 hymns. The numbers of the hymns are displayed by combining special small single-digit boards. What is the minimum number of small boards that is needed?
You had to think very carefully to answer this question. Amy from St Albans Primary School, Kevin from CIS, Hong Kong, Kirsty who goes to Steeple Morden and Ruth all reasoned it through very clearly. Here is Amy's argument:
Thank you for a very clear solution, Amy.