The CAS Registry Mumber 18841-60-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,8,8,4 and 1 respectively; the second part has 2 digits, 6 and 0 respectively. Calculate Digit Verification of CAS Registry Number 18841-60: (7*1)+(6*8)+(5*8)+(4*4)+(3*1)+(2*6)+(1*0)=126 126 % 10 = 6 So 18841-60-6 is a valid CAS Registry Number.