In my current addiction to all things pinterest, I have found a great site for quick math fact practice. It is called math magician and can be found here.
Remembering our math facts to 20 in both addition and subtraction is something about 90% of the class is still working on - regardless of grade. Of course, the grade 1's aren't expected to have this all down pat before the end of June. The grade 2's, however, should ideally already have this skill in their bank of math skills.
So, take a moment, go to the site and give it a try!