The CAS Registry Mumber 79319-39-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,9,3,1 and 9 respectively; the second part has 2 digits, 3 and 9 respectively. Calculate Digit Verification of CAS Registry Number 79319-39: (7*7)+(6*9)+(5*3)+(4*1)+(3*9)+(2*3)+(1*9)=164 164 % 10 = 4 So 79319-39-4 is a valid CAS Registry Number.