The CAS Registry Mumber 108843-93-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,8,8,4 and 3 respectively; the second part has 2 digits, 9 and 3 respectively. Calculate Digit Verification of CAS Registry Number 108843-93: (8*1)+(7*0)+(6*8)+(5*8)+(4*4)+(3*3)+(2*9)+(1*3)=142 142 % 10 = 2 So 108843-93-2 is a valid CAS Registry Number.