There are four word problems: two addition and two subtraction (all with regrouping). All four problems are solved incorrectly. The job of the student is to find the person's mistake, fix it, and explain with words what the student did wrong. This is a great extension activity for our higher achieving learners in second grade (but can be used for other grades)! The problems involve two-digit numbers with sums and differences under 100. There are two problems where it is solved in standard form a