The CAS Registry Mumber 610315-34-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 6,1,0,3,1 and 5 respectively; the second part has 2 digits, 3 and 4 respectively. Calculate Digit Verification of CAS Registry Number 610315-34: (8*6)+(7*1)+(6*0)+(5*3)+(4*1)+(3*5)+(2*3)+(1*4)=99 99 % 10 = 9 So 610315-34-9 is a valid CAS Registry Number.