The CAS Registry Mumber 97549-45-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,7,5,4 and 9 respectively; the second part has 2 digits, 4 and 5 respectively. Calculate Digit Verification of CAS Registry Number 97549-45: (7*9)+(6*7)+(5*5)+(4*4)+(3*9)+(2*4)+(1*5)=186 186 % 10 = 6 So 97549-45-6 is a valid CAS Registry Number.