Fifth graders build increasingly larger squares and triangles using pattern blocks. They record the growth patterns on a chart and look for corresponding numerical patterns. Students describe the patterns they find and use them to...

Fourth graders investigate the patterns associated with both triangular and square numbers. They use counters as manipulatives to depict the numbers as needed but focus on problem solving using mental math techniques.

Patterns of numbers don't come along every day, and so when they do, they need to be bragged about! The basic definition of triangular numbers begins this site which also lists many of the properties of these numbers, highlights the...