The CAS Registry Mumber 313689-14-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 3,1,3,6,8 and 9 respectively; the second part has 2 digits, 1 and 4 respectively. Calculate Digit Verification of CAS Registry Number 313689-14: (8*3)+(7*1)+(6*3)+(5*6)+(4*8)+(3*9)+(2*1)+(1*4)=144 144 % 10 = 4 So 313689-14-4 is a valid CAS Registry Number.