The CAS Registry Mumber 444081-49-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 4,4,4,0,8 and 1 respectively; the second part has 2 digits, 4 and 9 respectively. Calculate Digit Verification of CAS Registry Number 444081-49: (8*4)+(7*4)+(6*4)+(5*0)+(4*8)+(3*1)+(2*4)+(1*9)=136 136 % 10 = 6 So 444081-49-6 is a valid CAS Registry Number.