The Number Rack (also known as Rekenrek) 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.
To purchase Student Number Racks, click here.
- 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 educators with the theoretical basis, practical knowledge, and expertise to use a powerful mathematical tool called the Rekenrek. 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 5 and 10, 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 (listed above). Students solve imaginable and accessible problems using the key mathematical principles accessed through the rekenrek model, including cardinality, one-to-one-relationships, part-part-whole relationships, and subitizing.
Ten activities along with an introduction to using the Rekenrek or Number Rack. Includes correlations to the Common Core State Standards.
Build Your Own Number Rack
- 1 piece of mat board, 6" x 3"
- 2 black pipe cleaners
- 10 red beads
- 10 white beads
- 4 strips of tape
Along the short side of the mat board cut two small notches one inch from each edge. Thread five white beads followed by five red beads onto each pipe cleaner. Place each pipe cleaner onto the front of the matte board and fold the ends into the notches and around to the back. Secure pipe cleaner ends with tape.
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 www.clarity-innovations.com/apps.
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