The CAS Registry Mumber 85647-35-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,5,6,4 and 7 respectively; the second part has 2 digits, 3 and 5 respectively. Calculate Digit Verification of CAS Registry Number 85647-35: (7*8)+(6*5)+(5*6)+(4*4)+(3*7)+(2*3)+(1*5)=164 164 % 10 = 4 So 85647-35-4 is a valid CAS Registry Number.