The CAS Registry Mumber 155462-64-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,5,5,4,6 and 2 respectively; the second part has 2 digits, 6 and 4 respectively. Calculate Digit Verification of CAS Registry Number 155462-64: (8*1)+(7*5)+(6*5)+(5*4)+(4*6)+(3*2)+(2*6)+(1*4)=139 139 % 10 = 9 So 155462-64-9 is a valid CAS Registry Number.