The CAS Registry Mumber 1489-27-6 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 1,4,8 and 9 respectively; the second part has 2 digits, 2 and 7 respectively. Calculate Digit Verification of CAS Registry Number 1489-27: (6*1)+(5*4)+(4*8)+(3*9)+(2*2)+(1*7)=96 96 % 10 = 6 So 1489-27-6 is a valid CAS Registry Number.