The CAS Registry Mumber 134835-05-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,4,8,3 and 5 respectively; the second part has 2 digits, 0 and 5 respectively. Calculate Digit Verification of CAS Registry Number 134835-05: (8*1)+(7*3)+(6*4)+(5*8)+(4*3)+(3*5)+(2*0)+(1*5)=125 125 % 10 = 5 So 134835-05-5 is a valid CAS Registry Number.