The CAS Registry Mumber 127106-75-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,7,1,0 and 6 respectively; the second part has 2 digits, 7 and 5 respectively. Calculate Digit Verification of CAS Registry Number 127106-75: (8*1)+(7*2)+(6*7)+(5*1)+(4*0)+(3*6)+(2*7)+(1*5)=106 106 % 10 = 6 So 127106-75-6 is a valid CAS Registry Number.