The CAS Registry Mumber 126308-13-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,6,3,0 and 8 respectively; the second part has 2 digits, 1 and 3 respectively. Calculate Digit Verification of CAS Registry Number 126308-13: (8*1)+(7*2)+(6*6)+(5*3)+(4*0)+(3*8)+(2*1)+(1*3)=102 102 % 10 = 2 So 126308-13-2 is a valid CAS Registry Number.