The CAS Registry Mumber 29405-58-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,9,4,0 and 5 respectively; the second part has 2 digits, 5 and 8 respectively. Calculate Digit Verification of CAS Registry Number 29405-58: (7*2)+(6*9)+(5*4)+(4*0)+(3*5)+(2*5)+(1*8)=121 121 % 10 = 1 So 29405-58-1 is a valid CAS Registry Number.