The CAS Registry Mumber 85066-57-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,5,0,6 and 6 respectively; the second part has 2 digits, 5 and 7 respectively. Calculate Digit Verification of CAS Registry Number 85066-57: (7*8)+(6*5)+(5*0)+(4*6)+(3*6)+(2*5)+(1*7)=145 145 % 10 = 5 So 85066-57-5 is a valid CAS Registry Number.