The Math Learning Center (publisher of Bridges in Mathematics) has multiple free apps for math exploration and support. Below you will find links to a variety of their apps.
All apps can be found at: www.mathlearningcenter.org/apps
App selection includes: Fractions, Math Clock, Math Vocabulary Cards, Money Pieces, Number Chart, Number Line, Number Rack, Partial Product Finder, Pattern Shapes, and a Whiteboard App.