diff --git a/exercises/luhn/description.md b/exercises/luhn/description.md index ff8fa1926f..3929910e24 100644 --- a/exercises/luhn/description.md +++ b/exercises/luhn/description.md @@ -17,27 +17,27 @@ are disallowed. ## Example 1: valid credit card number ```text -4539 1488 0343 6467 +4539 3195 0343 6467 ``` The first step of the Luhn algorithm is to double every second digit, starting from the right. We will be doubling ```text -4_3_ 1_8_ 0_4_ 6_6_ +4_3_ 3_9_ 0_4_ 6_6_ ``` If doubling the number results in a number greater than 9 then subtract 9 from the product. The results of our doubling: ```text -8569 2478 0383 3437 +8569 6195 0383 3437 ``` Then sum all of the digits: ```text -8+5+6+9+2+4+7+8+0+3+8+3+3+4+3+7 = 80 +8+5+6+9+6+1+9+5+0+3+8+3+3+4+3+7 = 80 ``` If the sum is evenly divisible by 10, then the number is valid. This number is valid!