The CAS Registry Mumber 80498-75-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,0,4,9 and 8 respectively; the second part has 2 digits, 7 and 5 respectively. Calculate Digit Verification of CAS Registry Number 80498-75: (7*8)+(6*0)+(5*4)+(4*9)+(3*8)+(2*7)+(1*5)=155 155 % 10 = 5 So 80498-75-5 is a valid CAS Registry Number.