Why do this problem?
This activity was designed for the 2015 Young Mathematicians' Award
so it might be a particularly useful activity for a small group of your highest-attaining pupils to work on. It is a useful vehicle for developing systematic approaches. It can be used as an activity to encourage children to explain in written or spoken words what it is they have done.
Since this activity is aimed at the most confident mathematicians, there will not be much that you have to do to introduce it apart, perhaps, from letting the pupils declare their different ways of answering the first challenge.
Encourage them to discuss their thinking and reasoning as they progress through the challenges.
Tell me about how you are getting a solution for the challenge you are working on.
(The main thing when encouraging the pupils to use their skills is to avoid saying things about what you notice and directing them in your way of attempting a solution.)
Learners might like to try the other two challenges that were part of the Young Mathematicians' Award 2015: Open Boxes
and Centred Squares