Domino Sorting
1 out of 3
Try grouping the dominoes in the ways described. Are there any left over each time? Can you explain why?
Problem
Domino Sorting printable sheet
Here are some dominoes taken out of the full set:
Put the dominoes into pairs. The number of spots on each pair of dominoes must make a total of $5$.
How many pairs can you make?
Which dominoes are left over?
Can you pair them up in any different ways so that each pair adds to $5$?
Which dominoes are left over now?
Are there any dominoes which are always left over?
Can you explain why?
Getting Started
You might find it useful to find some real dominoes to use.
Have you added up or counted the spots on each domino?
Can you think of some pairs of numbers that add to five?
Student Solutions
Jack and Peter explained:
Well done, Jack and Peter. There are other ways to make pairs which total 5 and Thomas from Reading explains why:
Teachers' Resources
Using NRICH Tasks Richly describes ways in which teachers and learners can work with NRICH tasks in the classroom.
Why do this problem?
This problem will help learners to become more familiar with number bonds to five. It will also challenge them to justify findings.
Possible approach
If you have an interactive whiteboard, you may find our Dominoes Environment useful for this problem.
- How can you sort them?
- Can you make a pattern?
- Can you make a snake?
- What did you notice?
Key questions
Possible extension
You might want some children to find all the different ways of making pairs that add to $5$. This could be by picking two and then replacing them, or by finding all the different combinations which could be made at the same time (the problem as written focuses on the latter). Whichever way, part of their task should be to convince you that they have not missed any pairs out.
Domino Join Up is a similar problem which gives practice in number bonds to six, and could be used as an extension to this problem.
Possible support
Children would really benefit from having sets of dominoes to manipulate as this allows them to change their mind easily, so giving them more confidence to begin the task, and also prevents them from using any domino twice.