The CAS Registry Mumber 85930-87-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,5,9,3 and 0 respectively; the second part has 2 digits, 8 and 7 respectively. Calculate Digit Verification of CAS Registry Number 85930-87: (7*8)+(6*5)+(5*9)+(4*3)+(3*0)+(2*8)+(1*7)=166 166 % 10 = 6 So 85930-87-6 is a valid CAS Registry Number.