The CAS Registry Mumber 108343-88-0 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,8,3,4 and 3 respectively; the second part has 2 digits, 8 and 8 respectively. Calculate Digit Verification of CAS Registry Number 108343-88: (8*1)+(7*0)+(6*8)+(5*3)+(4*4)+(3*3)+(2*8)+(1*8)=120 120 % 10 = 0 So 108343-88-0 is a valid CAS Registry Number.