The CAS Registry Mumber 87035-69-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,7,0,3 and 5 respectively; the second part has 2 digits, 6 and 9 respectively. Calculate Digit Verification of CAS Registry Number 87035-69: (7*8)+(6*7)+(5*0)+(4*3)+(3*5)+(2*6)+(1*9)=146 146 % 10 = 6 So 87035-69-6 is a valid CAS Registry Number.