The CAS Registry Mumber 231949-60-3 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 2,3,1,9,4 and 9 respectively; the second part has 2 digits, 6 and 0 respectively. Calculate Digit Verification of CAS Registry Number 231949-60: (8*2)+(7*3)+(6*1)+(5*9)+(4*4)+(3*9)+(2*6)+(1*0)=143 143 % 10 = 3 So 231949-60-3 is a valid CAS Registry Number.