The CAS Registry Mumber 73878-96-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,3,8,7 and 8 respectively; the second part has 2 digits, 9 and 6 respectively. Calculate Digit Verification of CAS Registry Number 73878-96: (7*7)+(6*3)+(5*8)+(4*7)+(3*8)+(2*9)+(1*6)=183 183 % 10 = 3 So 73878-96-3 is a valid CAS Registry Number.