Below you will find a links that will help with TONS of reteaching exercises. Although I am not a huge worksheet teacher, these would be great to use in small group, home extensions, and independent practice. Just click the button. The kentucy link has TONS of printable games for MANY focus skills. These games would be great practice during reteaching or strategies time.
The following resource is great for beginning addition and subtraction. I love the progression and explanations! I can see it being valuable for reteaching in many grades. The file to download is below.