The CAS Registry Mumber 102712-35-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,2,7,1 and 2 respectively; the second part has 2 digits, 3 and 5 respectively. Calculate Digit Verification of CAS Registry Number 102712-35: (8*1)+(7*0)+(6*2)+(5*7)+(4*1)+(3*2)+(2*3)+(1*5)=76 76 % 10 = 6 So 102712-35-6 is a valid CAS Registry Number.