Number Rack for iPad, Web, and More

The Number Rack facilitates the natural development of children’s number sense. Rows of moveable, colored beads encourage learners to think in groups of fives and tens, helping them to explore and discover a variety of addition and subtraction strategies.

This virtual version of the manipulative is an open-ended educational tool, ideal for elementary classrooms and other learning environments that use laptops, Apple devices (e.g., iPhones, iPads), Chromebooks, or Windows devices.

For more resources including how to build your own student Number Racks for classroom use, click here.

The Number Rack is a key component of Bridges in Mathematics, second edition. Online preview available.

App Features

  • Display 1 to 10 rows of beads, 10 beads per row. On the iPhone, display up to 5 rows.
  • Hide beads with the resizable shade, which allows teachers or learners to model subtraction or difference problems.
  • Bead colors are reversed on rows 6 to 10 to distinguish groupings of 50 beads. Not available on iPhone or iPad Touch.
  • Use the drawing tools to annotate work and show understanding. Not available on iPhone or iPad Touch.
  • Write equations and expressions with the text tool. Not available on iPhone or iPad Touch.

Get more from this app

Book for Educators

This book provides teachers with the theoretical basis, practical knowledge, and expertise to use a powerful mathematical tool called the Rekenrek (also known as the Arithmetic Rack). Building on the idea that children must be able to “see” numbers within other numbers (e.g., 7 might be thought of as “5 and 2 more”), this book helps children recognize number combinations of five and ten, develop a rich sense of numbers between 0 and 20, and build a powerful set of intuitive strategies for addition and subtraction of both single and double digit numbers.

Supplemental Activity Book

This compilation of student-ready activities builds upon the contexts and learning objectives in Learning to Think Mathematically with the Rekenrek. Students solve imaginable, accessible problems motivating the key mathematical principles accessed through the rekenrek model, including cardinality, one-to-one-relationships, part-part-whole relationships, and subitizing.

Activity Book

Ten activities along with an introduction to using the Rekenrek or Number Rack. Includes correlations to the Common Core State Standards.


The Number Rack app was made possible by a generous donation from Dr. David Moursund.

Technical Support and Feedback

This app was crafted by Clarity Innovations: “We improve teaching and learning by creating solutions that match promising technologies with the needs of education.” For app support and feedback, contact them at

© 2017 Math Learning Center