The CAS Registry Mumber 68485-17-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,8,4,8 and 5 respectively; the second part has 2 digits, 1 and 7 respectively. Calculate Digit Verification of CAS Registry Number 68485-17: (7*6)+(6*8)+(5*4)+(4*8)+(3*5)+(2*1)+(1*7)=166 166 % 10 = 6 So 68485-17-6 is a valid CAS Registry Number.