The CAS Registry Mumber 65151-63-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,5,1,5 and 1 respectively; the second part has 2 digits, 6 and 3 respectively. Calculate Digit Verification of CAS Registry Number 65151-63: (7*6)+(6*5)+(5*1)+(4*5)+(3*1)+(2*6)+(1*3)=115 115 % 10 = 5 So 65151-63-5 is a valid CAS Registry Number.