The CAS Registry Mumber 127394-86-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,7,3,9 and 4 respectively; the second part has 2 digits, 8 and 6 respectively. Calculate Digit Verification of CAS Registry Number 127394-86: (8*1)+(7*2)+(6*7)+(5*3)+(4*9)+(3*4)+(2*8)+(1*6)=149 149 % 10 = 9 So 127394-86-9 is a valid CAS Registry Number.