The CAS Registry Mumber 68877-47-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,8,8,7 and 7 respectively; the second part has 2 digits, 4 and 7 respectively. Calculate Digit Verification of CAS Registry Number 68877-47: (7*6)+(6*8)+(5*8)+(4*7)+(3*7)+(2*4)+(1*7)=194 194 % 10 = 4 So 68877-47-4 is a valid CAS Registry Number.