The CAS Registry Mumber 486421-67-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 4,8,6,4,2 and 1 respectively; the second part has 2 digits, 6 and 7 respectively. Calculate Digit Verification of CAS Registry Number 486421-67: (8*4)+(7*8)+(6*6)+(5*4)+(4*2)+(3*1)+(2*6)+(1*7)=174 174 % 10 = 4 So 486421-67-4 is a valid CAS Registry Number.