The CAS Registry Mumber 132434-83-4 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 3 respectively. Calculate Digit Verification of CAS Registry Number 132434-83: (8*1)+(7*3)+(6*2)+(5*4)+(4*3)+(3*4)+(2*8)+(1*3)=104 104 % 10 = 4 So 132434-83-4 is a valid CAS Registry Number.