The CAS Registry Mumber 67091-96-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,7,0,9 and 1 respectively; the second part has 2 digits, 9 and 6 respectively. Calculate Digit Verification of CAS Registry Number 67091-96: (7*6)+(6*7)+(5*0)+(4*9)+(3*1)+(2*9)+(1*6)=147 147 % 10 = 7 So 67091-96-7 is a valid CAS Registry Number.