The CAS Registry Mumber 42529-29-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 4,2,5,2 and 9 respectively; the second part has 2 digits, 2 and 9 respectively. Calculate Digit Verification of CAS Registry Number 42529-29: (7*4)+(6*2)+(5*5)+(4*2)+(3*9)+(2*2)+(1*9)=113 113 % 10 = 3 So 42529-29-3 is a valid CAS Registry Number.