The CAS Registry Mumber 79512-43-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,9,5,1 and 2 respectively; the second part has 2 digits, 4 and 3 respectively. Calculate Digit Verification of CAS Registry Number 79512-43: (7*7)+(6*9)+(5*5)+(4*1)+(3*2)+(2*4)+(1*3)=149 149 % 10 = 9 So 79512-43-9 is a valid CAS Registry Number.