The CAS Registry Mumber 65356-05-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,5,3,5 and 6 respectively; the second part has 2 digits, 0 and 5 respectively. Calculate Digit Verification of CAS Registry Number 65356-05: (7*6)+(6*5)+(5*3)+(4*5)+(3*6)+(2*0)+(1*5)=130 130 % 10 = 0 So 65356-05-0 is a valid CAS Registry Number.