Notes on Geometric Weighted Check Digit Verification This note describes a method for utilizing geometric weight modulus 11 checking digits on a computer which does not have either multiplication or division. In addition some attempt has been made to show some limitations of this system. CACM December, 1961 Wilson, J. G. CA611208 JB March 15, 1978 10:17 PM 242 5 242 242 5 242 242 5 242