The CAS Registry Mumber 149439-87-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,4,9,4,3 and 9 respectively; the second part has 2 digits, 8 and 7 respectively. Calculate Digit Verification of CAS Registry Number 149439-87: (8*1)+(7*4)+(6*9)+(5*4)+(4*3)+(3*9)+(2*8)+(1*7)=172 172 % 10 = 2 So 149439-87-2 is a valid CAS Registry Number.