The CAS Registry Mumber 6367-09-5 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 6,3,6 and 7 respectively; the second part has 2 digits, 0 and 9 respectively. Calculate Digit Verification of CAS Registry Number 6367-09: (6*6)+(5*3)+(4*6)+(3*7)+(2*0)+(1*9)=105 105 % 10 = 5 So 6367-09-5 is a valid CAS Registry Number.