The CAS Registry Mumber 90151-43-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,0,1,5 and 1 respectively; the second part has 2 digits, 4 and 3 respectively. Calculate Digit Verification of CAS Registry Number 90151-43: (7*9)+(6*0)+(5*1)+(4*5)+(3*1)+(2*4)+(1*3)=102 102 % 10 = 2 So 90151-43-2 is a valid CAS Registry Number.