Addition and Subtraction
2.NBT.1: Place Value Work: www.opened.com/search?resource_type=game&standard=2.NBT.1
3.NBT.A.2: Add & Subtract Numbers to 1,000
4.NBT.B.4: Add & Subtract Multi-Digit Numbers
Drag & Drop Math (click on Addition or Subtraction)
Deep Sea Duel - be the first to find 3 numbers which add to the target number