The CAS Registry Mumber 81259-62-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,1,2,5 and 9 respectively; the second part has 2 digits, 6 and 2 respectively. Calculate Digit Verification of CAS Registry Number 81259-62: (7*8)+(6*1)+(5*2)+(4*5)+(3*9)+(2*6)+(1*2)=133 133 % 10 = 3 So 81259-62-3 is a valid CAS Registry Number.