The CAS Registry Mumber 123283-19-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,3,2,8 and 3 respectively; the second part has 2 digits, 1 and 9 respectively. Calculate Digit Verification of CAS Registry Number 123283-19: (8*1)+(7*2)+(6*3)+(5*2)+(4*8)+(3*3)+(2*1)+(1*9)=102 102 % 10 = 2 So 123283-19-2 is a valid CAS Registry Number.