The CAS Registry Mumber 75480-74-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,5,4,8 and 0 respectively; the second part has 2 digits, 7 and 4 respectively. Calculate Digit Verification of CAS Registry Number 75480-74: (7*7)+(6*5)+(5*4)+(4*8)+(3*0)+(2*7)+(1*4)=149 149 % 10 = 9 So 75480-74-9 is a valid CAS Registry Number.