The CAS Registry Mumber 79009-29-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,9,0,0 and 9 respectively; the second part has 2 digits, 2 and 9 respectively. Calculate Digit Verification of CAS Registry Number 79009-29: (7*7)+(6*9)+(5*0)+(4*0)+(3*9)+(2*2)+(1*9)=143 143 % 10 = 3 So 79009-29-3 is a valid CAS Registry Number.