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 must choose four different digits from $1 - 9$ and put one
in each box. For example:
This gives four two-digit numbers:
In this case their sum is $151$.
Your challenge is to find four different digits that give four
two-digit numbers which add to a total of $100$.
How many ways can you find of doing it?
This problem is adapted from
Make 200 from 'Mathematical Challenges for Able Pupils Key Stages 1
and 2', published by DfES. You can find out more about this book,
including how to order it, on the Standards website here .