The CAS Registry Mumber 1735-00-8 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 1,7,3 and 5 respectively; the second part has 2 digits, 0 and 0 respectively. Calculate Digit Verification of CAS Registry Number 1735-00: (6*1)+(5*7)+(4*3)+(3*5)+(2*0)+(1*0)=68 68 % 10 = 8 So 1735-00-8 is a valid CAS Registry Number.