The CAS Registry Mumber 125331-06-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,5,3,3 and 1 respectively; the second part has 2 digits, 0 and 6 respectively. Calculate Digit Verification of CAS Registry Number 125331-06: (8*1)+(7*2)+(6*5)+(5*3)+(4*3)+(3*1)+(2*0)+(1*6)=88 88 % 10 = 8 So 125331-06-8 is a valid CAS Registry Number.