The CAS Registry Mumber 1450-20-0 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 1,4,5 and 0 respectively; the second part has 2 digits, 2 and 0 respectively. Calculate Digit Verification of CAS Registry Number 1450-20: (6*1)+(5*4)+(4*5)+(3*0)+(2*2)+(1*0)=50 50 % 10 = 0 So 1450-20-0 is a valid CAS Registry Number.