The CAS Registry Mumber 19739-94-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,9,7,3 and 9 respectively; the second part has 2 digits, 9 and 4 respectively. Calculate Digit Verification of CAS Registry Number 19739-94: (7*1)+(6*9)+(5*7)+(4*3)+(3*9)+(2*9)+(1*4)=157 157 % 10 = 7 So 19739-94-7 is a valid CAS Registry Number.