The CAS Registry Mumber 945611-27-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 9,4,5,6,1 and 1 respectively; the second part has 2 digits, 2 and 7 respectively. Calculate Digit Verification of CAS Registry Number 945611-27: (8*9)+(7*4)+(6*5)+(5*6)+(4*1)+(3*1)+(2*2)+(1*7)=178 178 % 10 = 8 So 945611-27-8 is a valid CAS Registry Number.