The CAS Registry Mumber 7365-74-4 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,3,6 and 5 respectively; the second part has 2 digits, 7 and 4 respectively. Calculate Digit Verification of CAS Registry Number 7365-74: (6*7)+(5*3)+(4*6)+(3*5)+(2*7)+(1*4)=114 114 % 10 = 4 So 7365-74-4 is a valid CAS Registry Number.