The CAS Registry Mumber 84426-12-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,4,4,2 and 6 respectively; the second part has 2 digits, 1 and 2 respectively. Calculate Digit Verification of CAS Registry Number 84426-12: (7*8)+(6*4)+(5*4)+(4*2)+(3*6)+(2*1)+(1*2)=130 130 % 10 = 0 So 84426-12-0 is a valid CAS Registry Number.