Our exact problem is this: We have a ten digit number, 6134217948, and we need to find a check digit for it. We have a manual formula which invovles multiplying every other number, i.e. 1,4,1,9,8, by two, and then adding the sum of the resulting numbers to the sum of the rest, i.e. 6,3,2,7,4. However if any of the first string of numbers multiplied by two is larger than 9, than it drops the tenths digit and has a one added to it.

For example 1 4 1 9 8 individually multiplied by 2 equals 2 8 2 18 16, which is changed to 2 8 2 9 7.

After this is said and done the two strings are added back together, ie (2+4+2+9+7)+(6+3+2+7+4) and the ones column of the resulting number is subtracted from ten to equal our check digit number.

While we can manage all of this manually, we need help making a formula to mass produce this in excel.

Any help would be very welcome,

Thank You.