The CAS Registry Mumber 262352-58-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 2,6,2,3,5 and 2 respectively; the second part has 2 digits, 5 and 8 respectively. Calculate Digit Verification of CAS Registry Number 262352-58: (8*2)+(7*6)+(6*2)+(5*3)+(4*5)+(3*2)+(2*5)+(1*8)=129 129 % 10 = 9 So 262352-58-9 is a valid CAS Registry Number.