The CAS Registry Mumber 80595-71-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,0,5,9 and 5 respectively; the second part has 2 digits, 7 and 1 respectively. Calculate Digit Verification of CAS Registry Number 80595-71: (7*8)+(6*0)+(5*5)+(4*9)+(3*5)+(2*7)+(1*1)=147 147 % 10 = 7 So 80595-71-7 is a valid CAS Registry Number.