A triangular number or triangle number counts objects arranged in an equilateral triangle.

Spark your math thinking!

1. Set up your math mini spark recording page: #81 Triangular Numbers
2. Use this interactive tool to construct triangular numbers until you can see the pattern to answer this question.
3. This is a teaching page that REALLY gets into the math behind these types of problems. Use the formula and see if you can get the right answer to the counter problem.
4. When you have a solution and a written statement about what you did to solve the problem you can click here to see the solution.
5. Check out this triangular number chart.  After looking over the first page, click on “getting started” to explore this resource.
6. Connection: Research the original Lite-Brite, a 1960s toy. Come up with some unique ideas on how teachers can use these toys to teach math, science, and art.
7. Share your math mini spark recording page with your teacher/EY coordinator.

Image source: https://nzmaths.co.nz/sites/default/files/TriangularNumbers.pdf