The CAS Registry Mumber 118001-85-7 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,8,0,0 and 1 respectively; the second part has 2 digits, 8 and 5 respectively. Calculate Digit Verification of CAS Registry Number 118001-85: (8*1)+(7*1)+(6*8)+(5*0)+(4*0)+(3*1)+(2*8)+(1*5)=87 87 % 10 = 7 So 118001-85-7 is a valid CAS Registry Number.