The CAS Registry Mumber 23774-29-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,3,7,7 and 4 respectively; the second part has 2 digits, 2 and 9 respectively. Calculate Digit Verification of CAS Registry Number 23774-29: (7*2)+(6*3)+(5*7)+(4*7)+(3*4)+(2*2)+(1*9)=120 120 % 10 = 0 So 23774-29-0 is a valid CAS Registry Number.