The CAS Registry Mumber 132434-84-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,2,4,3 and 4 respectively; the second part has 2 digits, 8 and 4 respectively. Calculate Digit Verification of CAS Registry Number 132434-84: (8*1)+(7*3)+(6*2)+(5*4)+(4*3)+(3*4)+(2*8)+(1*4)=105 105 % 10 = 5 So 132434-84-5 is a valid CAS Registry Number.