The CAS Registry Mumber 81759-60-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,1,7,5 and 9 respectively; the second part has 2 digits, 6 and 0 respectively. Calculate Digit Verification of CAS Registry Number 81759-60: (7*8)+(6*1)+(5*7)+(4*5)+(3*9)+(2*6)+(1*0)=156 156 % 10 = 6 So 81759-60-6 is a valid CAS Registry Number.