The CAS Registry Mumber 131352-49-3 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,1,3,5 and 2 respectively; the second part has 2 digits, 4 and 9 respectively. Calculate Digit Verification of CAS Registry Number 131352-49: (8*1)+(7*3)+(6*1)+(5*3)+(4*5)+(3*2)+(2*4)+(1*9)=93 93 % 10 = 3 So 131352-49-3 is a valid CAS Registry Number.