I used this task with my 3rd grade students. The purpose of this task was to notice how to use regrouping when subtracting. I wanted students to recognize and understand when it is appropriate to regroup when subtracting. The students were given 2 different answers for the same subtraction problem. The student had to decide which answer was correct. The student had a place to include their claim and argument, as well as have time to discuss with a partner and record their partner’s thoughts.