The CAS Registry Mumber 3179-16-6 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 3,1,7 and 9 respectively; the second part has 2 digits, 1 and 6 respectively. Calculate Digit Verification of CAS Registry Number 3179-16: (6*3)+(5*1)+(4*7)+(3*9)+(2*1)+(1*6)=86 86 % 10 = 6 So 3179-16-6 is a valid CAS Registry Number.