The typical classroom seems to have a spread in grade level ability that varies somewhere between 2 to 6 grades. For instance, in your grade 8 class, the math ability will be anywhere from grade 4 ability to grade 10 ability. And you, as a teacher, must teach to them all and ensure that each of them reaches their potential! How, you ask? Well, like me, you're probably told to differentiate your instruction. You can search anywhere online and see that differentiated instruction is well defined. However, to get started, you need group work, get your class working in groups. When you're working with a specifc group, you'll need to figure out what the rest of the class is doing. One of the things that works really well for differentiated instruction is 'Literature Circles'. Check out the worksheets and give it an honest try.
Be sure to check out the Teacher Tube video on how to use literature circles in your classroom.