The CAS Registry Mumber 76368-88-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,6,3,6 and 8 respectively; the second part has 2 digits, 8 and 8 respectively. Calculate Digit Verification of CAS Registry Number 76368-88: (7*7)+(6*6)+(5*3)+(4*6)+(3*8)+(2*8)+(1*8)=172 172 % 10 = 2 So 76368-88-2 is a valid CAS Registry Number.