The CAS Registry Mumber 80524-43-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,0,5,2 and 4 respectively; the second part has 2 digits, 4 and 3 respectively. Calculate Digit Verification of CAS Registry Number 80524-43: (7*8)+(6*0)+(5*5)+(4*2)+(3*4)+(2*4)+(1*3)=112 112 % 10 = 2 So 80524-43-2 is a valid CAS Registry Number.