The CAS Registry Mumber 327069-26-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 3,2,7,0,6 and 9 respectively; the second part has 2 digits, 2 and 6 respectively. Calculate Digit Verification of CAS Registry Number 327069-26: (8*3)+(7*2)+(6*7)+(5*0)+(4*6)+(3*9)+(2*2)+(1*6)=141 141 % 10 = 1 So 327069-26-1 is a valid CAS Registry Number.