The CAS Registry Mumber 81276-67-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,1,2,7 and 6 respectively; the second part has 2 digits, 6 and 7 respectively. Calculate Digit Verification of CAS Registry Number 81276-67: (7*8)+(6*1)+(5*2)+(4*7)+(3*6)+(2*6)+(1*7)=137 137 % 10 = 7 So 81276-67-7 is a valid CAS Registry Number.