The CAS Registry Mumber 6560-62-9 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 6,5,6 and 0 respectively; the second part has 2 digits, 6 and 2 respectively. Calculate Digit Verification of CAS Registry Number 6560-62: (6*6)+(5*5)+(4*6)+(3*0)+(2*6)+(1*2)=99 99 % 10 = 9 So 6560-62-9 is a valid CAS Registry Number.