There are two main ways to deal with this situation. One is to have students work in groups where you mix the higher level students with the lower level students. This allows peer teaching to take place, where stronger students can assist weaker students. This is a great way for the stronger students to review. Of course, you don’t want to do this all of the time because it could lead to frustration. The other technique is to divide the class according to level. This means that you can then either spend a little more time with the weaker group as needed, or you can assign different tasks to better suit the students’ needs and ability. For example, the higher level group could work on either a more difficult task, or have a slightly longer version of the same task.