The CAS Registry Mumber 139886-30-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,9,8,8 and 6 respectively; the second part has 2 digits, 3 and 0 respectively. Calculate Digit Verification of CAS Registry Number 139886-30: (8*1)+(7*3)+(6*9)+(5*8)+(4*8)+(3*6)+(2*3)+(1*0)=179 179 % 10 = 9 So 139886-30-9 is a valid CAS Registry Number.