The CAS Registry Mumber 127243-67-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,7,2,4 and 3 respectively; the second part has 2 digits, 6 and 7 respectively. Calculate Digit Verification of CAS Registry Number 127243-67: (8*1)+(7*2)+(6*7)+(5*2)+(4*4)+(3*3)+(2*6)+(1*7)=118 118 % 10 = 8 So 127243-67-8 is a valid CAS Registry Number.