What is the one math concept that you still feel students have not quiet mastered in second grade? “Regrouping,” you say. Well before you pull another small group to line up place values and regroup to the tens, consider rebooting the regrouping instruction completely. Many 2nd graders are not ready to make sense of the standard algorithm for addition and subtraction and the standards do not require it. If students have not mastered the algorithm at this point in the year, chances are likely that the student’s number sense needs to be developed further. Check out this one minute Origo video, to see some strategies for developing a students’ understanding of addition with regrouping.