The CAS Registry Mumber 75869-73-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,5,8,6 and 9 respectively; the second part has 2 digits, 7 and 3 respectively. Calculate Digit Verification of CAS Registry Number 75869-73: (7*7)+(6*5)+(5*8)+(4*6)+(3*9)+(2*7)+(1*3)=187 187 % 10 = 7 So 75869-73-7 is a valid CAS Registry Number.