2.OA.B: Add and subtract within 20.
![](http://c.gigcount.com/wildfire/IMP/CXNID=2000002.0NXC/bT*xJmx*PTEzNjIyNzg4MjQ3NjUmcHQ9MTM2MjI3ODgyNjQ3NiZwPTk3NTA3MiZkPTAwMCUyMC*lMjBWb2tpJTIwV2lkZ2V*Jmc9/MSZvPWJkNDMxNzc4ZDEyYzQ4ZDg5ZWZhYjNmOWE5NDMwZjE4Jm9mPTA=.gif)
Second grade students are expected to be able to add and subtract fluently within 20. This means that students should be able to add any one-digit numbers together and fluently know the answer. If you are wondering what fluency is, it is the ability to know your math facts from memory, instead of having to add them up each time you are asked. Click on the links below to practice math fact fluency!
Use this addition table to help you add numbers quickly! Find the first number you're adding on the horizontal green line, and the second number you're adding on the vertical green line. Find the spot where they meet, and that is your answer.
For Students!
Click here to play Dude's Dilemma! In this excellent adding and subtracting game, you have to save Dude the Dog! He's stuck on the roof, and the only way to get him down is to fly in a helicopter and rescue him! Choose whether you would like to play addition or subtraction, and then choose "easy", "medium", or "hard" to pick the level of math facts you would like to answer. Answer the math facts as quickly as possible to save Dude the Dog!
For Teachers!
Click here to access great games and activities from the Bridges in Mathematics Second Grade Curriculum. These activities align to the Common Core State Standards and will assist with teaching your students how to add and subtract fluently within 20.