This product is used for the Kagan structure Rally coach. Partners work together to solve and coach. This product contains two-digit addition without regrouping. The sheets are differentiated into three groups a lower, middle, and high.Lower group (4 pages)2-digit by 1-digit addition within 20Middle group (4 pages)2-digit by 2-digit addition within 50Higher group (4 pages)2-digit by 2-digit addition within 100