The CAS Registry Mumber 79425-67-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,9,4,2 and 5 respectively; the second part has 2 digits, 6 and 7 respectively. Calculate Digit Verification of CAS Registry Number 79425-67: (7*7)+(6*9)+(5*4)+(4*2)+(3*5)+(2*6)+(1*7)=165 165 % 10 = 5 So 79425-67-5 is a valid CAS Registry Number.