I was lucky to have the opportunity to guest post for Raki's Rad Resources last week. I told about a few games that can be played using a regular deck of cards, that can be used to develop mastery of basic addition and subtraction facts, and work on this standard from the Common Core: 2.OA.2. Fluently add and subtract within 20 using mental strategies.2 By end of Grade 2, know from memory all sums of two one-digit numbers.
I think this is probably the toughest standard for the little ones to master, and I'm constantly on the lookout for activities that will lead to mastery of these facts. Be sure to stop by Elementary Matters to see more about these games and how to get the above freebie!