The CAS Registry Mumber 2244-27-1 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 2,2,4 and 4 respectively; the second part has 2 digits, 2 and 7 respectively. Calculate Digit Verification of CAS Registry Number 2244-27: (6*2)+(5*2)+(4*4)+(3*4)+(2*2)+(1*7)=61 61 % 10 = 1 So 2244-27-1 is a valid CAS Registry Number.