The CAS Registry Mumber 416864-79-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 4,1,6,8,6 and 4 respectively; the second part has 2 digits, 7 and 9 respectively. Calculate Digit Verification of CAS Registry Number 416864-79: (8*4)+(7*1)+(6*6)+(5*8)+(4*6)+(3*4)+(2*7)+(1*9)=174 174 % 10 = 4 So 416864-79-4 is a valid CAS Registry Number.