Who Wants to be a Mathonaire

Who Wants to be a Mathonaire
You have to try to reach one million points by answering maths questions.  There are 5 levels of difficulty.

Manga High Math Games

Manga High Math -Brought to you by Dr. Marcus du Sautoy OBE, Professor of Mathematics at University of Oxford, and his team, Manga High offers graphically rich maths games aimed at teenagers. Using exciting contexts within timed games, students answer questions in order to unlock higher levels and increase their position on the Leaderboard. 9 of the Manga High games are offered on their free package.

Guess Your Number... Hmmm How Does This Work??

Guess Your Number... Hmmm How Does This Work??

Who Wants To Be A Mathionaire

Who Wants To Be A Mathionaire found on Math is Fun.

Hooda Math

Hooda Math - Some great games to reinforce content. 

Calculation Nation- Great Math Games

Calculation Nation
The games of Calculation Nation™ are organized around content from the upper elementary and middle grades math curriculum. By becoming a citizen of Calculation Nation™, your child or student will play online math strategy games that allow them to learn about fractions, factors, multiples, symmetry and more, as well as practice important skills like basic multiplication and calculating area — all while having fun.

Students can challenge others or themselves to cool games like Square Off. -
Perimeter, area, and alien spaceships — oh, my! The more ships you capture and area you cover, the more you score.

This would be great for high school special needs students.