The CAS Registry Mumber 85291-58-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,5,2,9 and 1 respectively; the second part has 2 digits, 5 and 8 respectively. Calculate Digit Verification of CAS Registry Number 85291-58: (7*8)+(6*5)+(5*2)+(4*9)+(3*1)+(2*5)+(1*8)=153 153 % 10 = 3 So 85291-58-3 is a valid CAS Registry Number.