The CAS Registry Mumber 60603-13-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,0,6,0 and 3 respectively; the second part has 2 digits, 1 and 3 respectively. Calculate Digit Verification of CAS Registry Number 60603-13: (7*6)+(6*0)+(5*6)+(4*0)+(3*3)+(2*1)+(1*3)=86 86 % 10 = 6 So 60603-13-6 is a valid CAS Registry Number.