Why do this problem?
This practical problem
can be very engaging. It has the ability to introduce pupils to some logical reasoning as well as being solvable by trial and improvement.
You could put eight cubes (of the correct colours) together to make a large cube without there being one of each colour on each face. Ask children what they notice. Give time for them to consider this individually then suggest they talk with a partner. Finally, you can draw the whole group together to share ideas.
Hopefully that initial discussion will have brought up some of the attributes of the large cube so you can introduce learners to the challenge itself. Plenty of cubes will be required for children to try out their ideas.
After a short time, bring everyone together for a 'mini plenary' where progress is discussed. This can help children articulate their ideas so far and it gives others a helping hand if they have found it hard to get started.
In the plenary, you could ask a few pupils to share some particularly useful ways of approaching this problem, perhaps because they have worked systematically.
How are you trying to solve this?
Have you checked each face has one of each colour cube?
Having a collection of coloured cubes available will help all children have a go at this problem.