1. Calculator Tricks 1 By Brian Carruthers ( (Please see notes on slide 1)

2. Is that your final answer?

3. Pick a number between 1 and 9

4. Use a calculator to:  Multiply your number it by 9.  Then multiply it by:  12,345,679

5. If you show me the result on your calculator I can tell you the original number you selected

6. You don’t believe me? Do you?

7. Watch this:  1 = 111,111,111  2 = 222,222,222  3 = 333,333,333  4 = 444,444,444  5 = 555,555,555  6 = 666,666,666  7 = 777,777,777  8 = 888,888,888  9 = 999,999,999

8. How did I know?  9 x 12345679 = 111111111.  You multiplied your number by 111111111.  By the way, the 8-digit number (12,345,679) should be easily memorised:  only the 8 is missing from the sequence.

9. Now what did you think of that?