The CAS Registry Mumber 64966-11-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,4,9,6 and 6 respectively; the second part has 2 digits, 1 and 1 respectively. Calculate Digit Verification of CAS Registry Number 64966-11: (7*6)+(6*4)+(5*9)+(4*6)+(3*6)+(2*1)+(1*1)=156 156 % 10 = 6 So 64966-11-6 is a valid CAS Registry Number.