The CAS Registry Mumber 125145-66-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,5,1,4 and 5 respectively; the second part has 2 digits, 6 and 6 respectively. Calculate Digit Verification of CAS Registry Number 125145-66: (8*1)+(7*2)+(6*5)+(5*1)+(4*4)+(3*5)+(2*6)+(1*6)=106 106 % 10 = 6 So 125145-66-6 is a valid CAS Registry Number.