*Barcodes - introduce an 11 digit code for each item, with the fist 10 digits x1,x2....x10 being information digits and x11 being the check digit. Each digit is a decimal digit (one of 0,1,.......8,9). The check digit is calculated so that:

x1-x2+x3-x4+x5-x6+x7-x8+x9-x10+x11 =0 (mod 10)

- calculate the check digit if the information digits are 0987654321.

-explain why the code is not able to detect the

interchange of two adjacent digits for certain values of the digit!!!!! help

Any help is greatly appreciated!!!