The CAS Registry Mumber 2146-27-2 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 2,1,4 and 6 respectively; the second part has 2 digits, 2 and 7 respectively. Calculate Digit Verification of CAS Registry Number 2146-27: (6*2)+(5*1)+(4*4)+(3*6)+(2*2)+(1*7)=62 62 % 10 = 2 So 2146-27-2 is a valid CAS Registry Number.