The CAS Registry Mumber 94565-55-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,4,5,6 and 5 respectively; the second part has 2 digits, 5 and 5 respectively. Calculate Digit Verification of CAS Registry Number 94565-55: (7*9)+(6*4)+(5*5)+(4*6)+(3*5)+(2*5)+(1*5)=166 166 % 10 = 6 So 94565-55-6 is a valid CAS Registry Number.