The CAS Registry Mumber 133847-32-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,3,8,4 and 7 respectively; the second part has 2 digits, 3 and 2 respectively. Calculate Digit Verification of CAS Registry Number 133847-32: (8*1)+(7*3)+(6*3)+(5*8)+(4*4)+(3*7)+(2*3)+(1*2)=132 132 % 10 = 2 So 133847-32-2 is a valid CAS Registry Number.