The CAS Registry Mumber 75425-74-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,5,4,2 and 5 respectively; the second part has 2 digits, 7 and 4 respectively. Calculate Digit Verification of CAS Registry Number 75425-74: (7*7)+(6*5)+(5*4)+(4*2)+(3*5)+(2*7)+(1*4)=140 140 % 10 = 0 So 75425-74-0 is a valid CAS Registry Number.