Here are some websites to help prepare you for the state test.
Below are specific links for additional practice for each unit:
Unit 1
http://www.ixl.com/math/grade-8/estimate-positive-and-negative-square-roots
http://www.ixl.com/math/grade-8/estimate-cube-roots
http://www.ixl.com/math/grade-8/compare-percents-to-fractions-and-decimals
Unit 2
http://www.ixl.com/math/grade-8/solve-proportions
http://www.ixl.com/math/grade-8/solve-proportions-word-problems
http://www.ixl.com/math/grade-8/write-variable-expressions
http://www.ixl.com/math/grade-8/write-variable-expressions-to-represent-diagrams
http://www.ixl.com/math/grade-8/solve-equations-involving-like-terms
http://www.ixl.com/math/grade-8/solve-multi-step-equations
http://www.ixl.com/math/grade-8/write-and-solve-equations-that-represent-diagrams
http://www.ixl.com/math/grade-8/identities-and-equations-with-no-solutions
http://www.ixl.com/math/grade-8/evaluate-multi-variable-expressions
http://www.ixl.com/math/grade-8/add-and-subtract-like-terms
Unit 3
http://www.ixl.com/math/grade-8/convert-between-standard-and-scientific-notation
http://www.ixl.com/math/grade-8/compare-numbers-written-in-scientific-notation
http://www.ixl.com/math/grade-8