The CAS Registry Mumber 80255-07-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,0,2,5 and 5 respectively; the second part has 2 digits, 0 and 7 respectively. Calculate Digit Verification of CAS Registry Number 80255-07: (7*8)+(6*0)+(5*2)+(4*5)+(3*5)+(2*0)+(1*7)=108 108 % 10 = 8 So 80255-07-8 is a valid CAS Registry Number.