The CAS Registry Mumber 144072-43-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,4,4,0,7 and 2 respectively; the second part has 2 digits, 4 and 3 respectively. Calculate Digit Verification of CAS Registry Number 144072-43: (8*1)+(7*4)+(6*4)+(5*0)+(4*7)+(3*2)+(2*4)+(1*3)=105 105 % 10 = 5 So 144072-43-5 is a valid CAS Registry Number.