The CAS Registry Mumber 74869-50-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,4,8,6 and 9 respectively; the second part has 2 digits, 5 and 0 respectively. Calculate Digit Verification of CAS Registry Number 74869-50: (7*7)+(6*4)+(5*8)+(4*6)+(3*9)+(2*5)+(1*0)=174 174 % 10 = 4 So 74869-50-4 is a valid CAS Registry Number.