The CAS Registry Mumber 66244-06-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,6,2,4 and 4 respectively; the second part has 2 digits, 0 and 6 respectively. Calculate Digit Verification of CAS Registry Number 66244-06: (7*6)+(6*6)+(5*2)+(4*4)+(3*4)+(2*0)+(1*6)=122 122 % 10 = 2 So 66244-06-2 is a valid CAS Registry Number.