Number Rack for iPhone, iPad, and the Web

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 iPod Touches, iPhones, or iPads. 

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.

Number Rack App Features

• Display 1 to 5 rows of beads, 10 beads per row. On the iPad, display up to 10 rows.
• Hide beads with the resizable shade, which allows teachers or learners to model subtraction or difference problems. For example,  if there are 20 beads in all and 17 are visible, how many are behind the shade? Or posed as an equation: 17 + ? = 20.
• Use the “start over” button to quickly reset all the beads and begin a new exploration.

Acknowledgements

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