The CAS Registry Mumber 146398-77-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,4,6,3,9 and 8 respectively; the second part has 2 digits, 7 and 7 respectively. Calculate Digit Verification of CAS Registry Number 146398-77: (8*1)+(7*4)+(6*6)+(5*3)+(4*9)+(3*8)+(2*7)+(1*7)=168 168 % 10 = 8 So 146398-77-8 is a valid CAS Registry Number.