The CAS Registry Mumber 163702-19-0 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,6,3,7,0 and 2 respectively; the second part has 2 digits, 1 and 9 respectively. Calculate Digit Verification of CAS Registry Number 163702-19: (8*1)+(7*6)+(6*3)+(5*7)+(4*0)+(3*2)+(2*1)+(1*9)=120 120 % 10 = 0 So 163702-19-0 is a valid CAS Registry Number.