expressions and equations with variables try a few of each :-)
http://www.ixl.com/math/grade-6/evaluate-multi-variable-expressions
http://www.ixl.com/math/grade-6/solve-two-step-equations
http://www.ixl.com/math/grade-7/evaluate-multi-variable-expressions
http://www.ixl.com/math/grade-7/evaluate-variable-expressions-for-numerators-and-denominators
http://www.ixl.com/math/grade-7/add-and-subtract-like-terms
http://www.ixl.com/math/grade-7/does-x-satisfy-the-equation
http://www.ixl.com/math/grade-7/solve-two-step-linear-equations
http://www.ixl.com/math/grade-7/solve-equations-involving-like-terms
http://www.ixl.com/math/grade-6/evaluate-multi-variable-expressions
http://www.ixl.com/math/grade-6/solve-two-step-equations
http://www.ixl.com/math/grade-7/evaluate-multi-variable-expressions
http://www.ixl.com/math/grade-7/evaluate-variable-expressions-for-numerators-and-denominators
http://www.ixl.com/math/grade-7/add-and-subtract-like-terms
http://www.ixl.com/math/grade-7/does-x-satisfy-the-equation
http://www.ixl.com/math/grade-7/solve-two-step-linear-equations
http://www.ixl.com/math/grade-7/solve-equations-involving-like-terms
Probability and Statistics
Calculate the probability as a percent and win "cash!"
http://www.xpmath.com/forums/arcade.php?do=play&gameid=98
Calculate the probability of landing on a particular color on a spinner
http://www.softschools.com/math/probability_and_statistics/probability_games/
Take a probability quiz
http://www.softschools.com/quizzes/math/what_is_the_probability/quiz3247.html
Match the given probability with the correct spinner
http://www.harcourtschool.com/activity/probability_circus/
Watch a video about theoretical and experimental probability
http://www.pbslearningmedia.org/resource/vtl07.math.data.col.whendoes50/when-does-50-50-become-50-50/
study jams video about outcomes and predictions
http://studyjams.scholastic.com/studyjams/jams/math/probability/pidentify-outcomes.htm
Khan Academy basic probability video and 5 question quiz
https://www.khanacademy.org/math/precalculus/prob_comb/basic_prob_precalc/v/basic-probability
https://www.khanacademy.org/math/precalculus/prob_comb/basic_prob_precalc/v/events-and-outcomes-1https://www.khanacademy.org/math/precalculus/prob_comb/basic_prob_precalc/e/probability_1
Combinations and permutations
http://www.mathsisfun.com/combinatorics/combinations-permutations.html
permutations
https://www.youtube.com/watch?v=hJRXKq2GEo8
permutations
https://www.youtube.com/watch?v=1stIqr0FGiE
combinations vs permutations
https://www.youtube.com/watch?v=PSS3mCS_Ef8
Calculate the probability as a percent and win "cash!"
http://www.xpmath.com/forums/arcade.php?do=play&gameid=98
Calculate the probability of landing on a particular color on a spinner
http://www.softschools.com/math/probability_and_statistics/probability_games/
Take a probability quiz
http://www.softschools.com/quizzes/math/what_is_the_probability/quiz3247.html
Match the given probability with the correct spinner
http://www.harcourtschool.com/activity/probability_circus/
Watch a video about theoretical and experimental probability
http://www.pbslearningmedia.org/resource/vtl07.math.data.col.whendoes50/when-does-50-50-become-50-50/
study jams video about outcomes and predictions
http://studyjams.scholastic.com/studyjams/jams/math/probability/pidentify-outcomes.htm
Khan Academy basic probability video and 5 question quiz
https://www.khanacademy.org/math/precalculus/prob_comb/basic_prob_precalc/v/basic-probability
https://www.khanacademy.org/math/precalculus/prob_comb/basic_prob_precalc/v/events-and-outcomes-1https://www.khanacademy.org/math/precalculus/prob_comb/basic_prob_precalc/e/probability_1
Combinations and permutations
http://www.mathsisfun.com/combinatorics/combinations-permutations.html
permutations
https://www.youtube.com/watch?v=hJRXKq2GEo8
permutations
https://www.youtube.com/watch?v=1stIqr0FGiE
combinations vs permutations
https://www.youtube.com/watch?v=PSS3mCS_Ef8