The CAS Registry Mumber 108132-72-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,8,1,3 and 2 respectively; the second part has 2 digits, 7 and 2 respectively. Calculate Digit Verification of CAS Registry Number 108132-72: (8*1)+(7*0)+(6*8)+(5*1)+(4*3)+(3*2)+(2*7)+(1*2)=95 95 % 10 = 5 So 108132-72-5 is a valid CAS Registry Number.