The CAS Registry Mumber 85259-35-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,5,2,5 and 9 respectively; the second part has 2 digits, 3 and 5 respectively. Calculate Digit Verification of CAS Registry Number 85259-35: (7*8)+(6*5)+(5*2)+(4*5)+(3*9)+(2*3)+(1*5)=154 154 % 10 = 4 So 85259-35-4 is a valid CAS Registry Number.