As you observe and meet with students during the beginning of the week, make notes about where each student falls according to their success with the objective for the week. For example, if you're teaching addition facts up to 10, and you see a child is still struggling, you might write their name in the "low" column. Then as you see other students struggling, add them to the low column. Now you have created a small group for interventions. On the flip side, if you see students excelling beyond the objective, you can put them in the "high" group and plan to meet with those students to extension. I use this sheet during math stations as I meet with 2 groups each day to teach and evaluate what they have mastered from our whole group lessons. Then, I can meet with them on the 2nd 2 days of math stations and support them.