The CAS Registry Mumber 350716-67-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 3,5,0,7,1 and 6 respectively; the second part has 2 digits, 6 and 7 respectively. Calculate Digit Verification of CAS Registry Number 350716-67: (8*3)+(7*5)+(6*0)+(5*7)+(4*1)+(3*6)+(2*6)+(1*7)=135 135 % 10 = 5 So 350716-67-5 is a valid CAS Registry Number.