Kakooma:

Kakooma starts with a deceptively simple idea: in a group of numbers, find the number that is the sum of two others. Sounds easy, right? Sometimes it is, but other times the answer is right in front of you and you just canâ€™t see it. To solve a single puzzle, you often end up doing dozens of calculations in your head, sometimes more than a hundred! Before you know it, your mind is sharper and your math skills are better.

http://gregtangmath.com/kakooma

Button Beach Challenge:

Solve all three levels of brain teasers and logic problems to reach the treasure.

http://www.amblesideprimary.com/ambleweb/mentalmaths/buttons.html

PowerLine1:

Place the power cells in the correct circles to advance to the next level.

http://www.oswego.org/ocsd-web/games/Powerlines/powerlines1.html

Powerlines 2:

http://www.oswego.org/ocsd-web/games/Powerlines/powerlines2.html

Powerline3:

http://www.oswego.org/ocsd-web/games/Powerlines/powerlines3.html

Tower of Hanoi:

Move all of the rings from the left pole to the right pole so the numbers are ordered greatest to least. It's harder than you think!

http://www.abcya.com/tower_of_hanoi.htm