Here is a list of websites and apps demonstrated during my session at NYSCATE 2013.
EngageNY.org: where you can download the full curriculum modules for free.
commoncore.org: access Eureka, the interface for the full math curriculum modules.
Number Pieces (Free): Virtual Base 10 blocks and whiteboard
AL Abacus ($1.99): Virtual abacus, sometimes called a Rekenrek
10 Frame Fill (Free): Basic ten-frame game/app.
Virtual Manipulatives! (Free): Fraction, decimal and percentage tiles
Teaching Table ($2.99): Smartboard-like manipulatives and interactivity for math presentations
Number Bonds: Addition & Subtraction to 99 ($1.99): Number bonds app for composing and decomposing numbers
Bugsy Kindergarten Math ($2.99): Fun game to practice K-1 skills
Splash Math website & apps ($9.99 per grade level): Adaptive Common Core-aligned math practice, with individual users
Numberland ($2.99): Montessori-based early numbers practice
Marble Math ($2.99): Game-interfaced math practice with choice of levels & subjects
Hands-on Equations ($4.99): Learn to solve for a variable step-by-step from concept to procedure
Thinking Blocks (All apps free): Solve word problems while making models interactively
Conceptua Math: Online tools and curriculum for math. Very strong for fractions.
Common Core Standards Viewer (Free): Interactive Common Core standards viewer with flow from one to the next