The CAS Registry Mumber 162047-17-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,6,2,0,4 and 7 respectively; the second part has 2 digits, 1 and 7 respectively. Calculate Digit Verification of CAS Registry Number 162047-17: (8*1)+(7*6)+(6*2)+(5*0)+(4*4)+(3*7)+(2*1)+(1*7)=108 108 % 10 = 8 So 162047-17-8 is a valid CAS Registry Number.