The 7-11-13 trick!

This trick makes you look like your brain is a mega fast calculator!

 

Ask a friend to write down ANY three digit number such as 231 or 884. Ask them to multiply the 

number by

x 7

x 11

x 13

...but even if your friend has used a calculator, you will have written down the answer ages ago! It's

fiendish!

 

THE SECRET: 

         all you do is write out the starting number twice! So 231 will become 231231 and 884 will 

become 884884. You don't believe it? Well try it on this calculator and see for yourself! You work 

this calculator by clicking the mouse on the buttons. Go on, put in ANY three digit number then 

x7x11 x 13 and see what you get!