The Magic Brain Calculator was a device used many years ago (mabye 1950′s) to solve maths problems. It requires you reset it to all zero’s to begin with and after a bit of practise you can solve many types of mathematical calculations. Clearing the device is just a matter of pulling the metal bar at the top of the machine and pushing it back in. Calculations of up to 8 digits can be performed such as addition, subtraction and multiplication. There are no details on if this device can divide although I am sure the brainy ones among you could work that out. The system works by using the stylus to drag the columns of numbers either up or down depending on the calculation you are performing. By doing this, and in the right order the numbers at the top will eventually give you the answer you need.
I am unable to find if the Magic Brain Calculator is still available although with a bit of hunting I bet you could track one down. It was built in Japan almost 60 years ago so good luck!
Via: Computer Museum