The CAS Registry Mumber 134140-99-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,4,1,4 and 0 respectively; the second part has 2 digits, 9 and 9 respectively. Calculate Digit Verification of CAS Registry Number 134140-99: (8*1)+(7*3)+(6*4)+(5*1)+(4*4)+(3*0)+(2*9)+(1*9)=101 101 % 10 = 1 So 134140-99-1 is a valid CAS Registry Number.