NRICH - One Big Triangle

Addition, Number Bonds
Key Stage: 1 ★

Can you place the small triangles in the large triangle so that the numbers that touch add up to 10.

This problem is useful for recalling and learning all the pairs of numbers with a total of 10 and working out the corresponding subtraction facts. The interactive version will help children to remain engaged with the problem as it is easy to use. However, for children who are fluent with the combinations to ten, this problem is still relevant because of the element of logic. If using the cards, learners will need to visualise triangles in different orientations to solve the problem.

This resource has comprehensive teachers' notes and resources, linked from the problem page. This includes possible approaches and key questions, as well as possible support and extensions.


The file attached is a HTML file, which, when opened, automatically redirects you to the problem on the NRICH website.