The CAS Registry Mumber 127855-49-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,7,8,5 and 5 respectively; the second part has 2 digits, 4 and 9 respectively. Calculate Digit Verification of CAS Registry Number 127855-49: (8*1)+(7*2)+(6*7)+(5*8)+(4*5)+(3*5)+(2*4)+(1*9)=156 156 % 10 = 6 So 127855-49-6 is a valid CAS Registry Number.