The CAS Registry Mumber 132949-42-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,2,9,4 and 9 respectively; the second part has 2 digits, 4 and 2 respectively. Calculate Digit Verification of CAS Registry Number 132949-42: (8*1)+(7*3)+(6*2)+(5*9)+(4*4)+(3*9)+(2*4)+(1*2)=139 139 % 10 = 9 So 132949-42-9 is a valid CAS Registry Number.