The CAS Registry Mumber 50868-64-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,0,8,6 and 8 respectively; the second part has 2 digits, 6 and 4 respectively. Calculate Digit Verification of CAS Registry Number 50868-64: (7*5)+(6*0)+(5*8)+(4*6)+(3*8)+(2*6)+(1*4)=139 139 % 10 = 9 So 50868-64-9 is a valid CAS Registry Number.