The CAS Registry Mumber 4671-92-5 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,6,7 and 1 respectively; the second part has 2 digits, 9 and 2 respectively. Calculate Digit Verification of CAS Registry Number 4671-92: (6*4)+(5*6)+(4*7)+(3*1)+(2*9)+(1*2)=105 105 % 10 = 5 So 4671-92-5 is a valid CAS Registry Number.