Friday, April 23, 2010

The Test figure in a Credit Cards

The Test figure in a Credit Cards

Take a Visa Credit Card with the Number

0699 0043 1313 9642


Count the Separate figures, starting fRom the Right. The 2

Thus becomes the first figure and the 0 on the left the sixteenth. Now write down under the number

all figures in the odd positions:

0699 0043 1313 9642
6 9 0 3 3 3 6 2


Double The figures in the even postions and again enter the result below the original

NUmber. If the result of doubling a figure is greater than 9 , Subtract 9.



This gives us,

0699 0043 1313 9642

0699 0083 2323 9682


Now add the figure in the bottom line:


0 + 6 + 9 + 9 + 0 + 0 + 8 + 3 + 2 + 3 + 2 + 3 + 9 +
6 + 8 + 2


With a visa Card number, the result must be divisible by 10. In our case

the sum is 70, as it should be. The opposite does not apply. If a number divisible by 10 is obtained

it does not necessarily follow that the original number was a Visa Credit Card Number.

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