The CAS Registry Mumber 2445-11-6 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 2,4,4 and 5 respectively; the second part has 2 digits, 1 and 1 respectively. Calculate Digit Verification of CAS Registry Number 2445-11: (6*2)+(5*4)+(4*4)+(3*5)+(2*1)+(1*1)=66 66 % 10 = 6 So 2445-11-6 is a valid CAS Registry Number.