Understanding Place Value: The Story of Infinity Street

Students who have a solid foundation in place value are often the ones who move forward most confidently in math. Too often, this area doesn't get the followup activity it so rightly deserves, but it’s one of the most important building blocks for future math understanding.

We revisited one of my favorite Montessori lessons — The Infinity Street Story. This classic presentation is introduced at the beginning of the Lower Elementary cycle, and it helps children visualize and feel the vastness of our number system.

The story imagines numbers as families living in houses along an endless street — each house belonging to a different “number family” and using the familiar color coded system for units (green), 10's (blue), 100's (red), and so on. As the story unfolds, the street continues forever, moving from thousands to millions, billions, trillions, and beyond — often all the way to nonillions (and sometimes further!).

After hearing the story, students worked with a variety of materials and tasks to read, record, and build large quantities — numbers like thirty-two quadrillion, six hundred twenty-two thousand and sixty-five. They now understand not just how to say big numbers, but what each place actually means.

We tied this lesson into our study of word etymology, exploring the historical roots of number words — bi, tri, quad, quin, and others. We also connected it to our word study with prefixes, deepening understanding of how language and math often share the same roots.

Here’s a friendly video demonstration of Infinity Street: https://youtu.be/-RmCjV5hLc4?si=9DEeCEJh_W5e08Kp