The CAS Registry Mumber 85697-86-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,5,6,9 and 7 respectively; the second part has 2 digits, 8 and 6 respectively. Calculate Digit Verification of CAS Registry Number 85697-86: (7*8)+(6*5)+(5*6)+(4*9)+(3*7)+(2*8)+(1*6)=195 195 % 10 = 5 So 85697-86-5 is a valid CAS Registry Number.