The CAS Registry Mumber 5033-17-0 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 5,0,3 and 3 respectively; the second part has 2 digits, 1 and 7 respectively. Calculate Digit Verification of CAS Registry Number 5033-17: (6*5)+(5*0)+(4*3)+(3*3)+(2*1)+(1*7)=60 60 % 10 = 0 So 5033-17-0 is a valid CAS Registry Number.