The CAS Registry Mumber 868-52-0 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 8,6 and 8 respectively; the second part has 2 digits, 5 and 2 respectively. Calculate Digit Verification of CAS Registry Number 868-52: (5*8)+(4*6)+(3*8)+(2*5)+(1*2)=100 100 % 10 = 0 So 868-52-0 is a valid CAS Registry Number.