The CAS Registry Mumber 102271-68-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,2,2,7 and 1 respectively; the second part has 2 digits, 6 and 8 respectively. Calculate Digit Verification of CAS Registry Number 102271-68: (8*1)+(7*0)+(6*2)+(5*2)+(4*7)+(3*1)+(2*6)+(1*8)=81 81 % 10 = 1 So 102271-68-1 is a valid CAS Registry Number.