The CAS Registry Mumber 80233-19-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,0,2,3 and 3 respectively; the second part has 2 digits, 1 and 9 respectively. Calculate Digit Verification of CAS Registry Number 80233-19: (7*8)+(6*0)+(5*2)+(4*3)+(3*3)+(2*1)+(1*9)=98 98 % 10 = 8 So 80233-19-8 is a valid CAS Registry Number.