The CAS Registry Mumber 7279-45-0 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,2,7 and 9 respectively; the second part has 2 digits, 4 and 5 respectively. Calculate Digit Verification of CAS Registry Number 7279-45: (6*7)+(5*2)+(4*7)+(3*9)+(2*4)+(1*5)=120 120 % 10 = 0 So 7279-45-0 is a valid CAS Registry Number.