The CAS Registry Mumber 618070-68-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 6,1,8,0,7 and 0 respectively; the second part has 2 digits, 6 and 8 respectively. Calculate Digit Verification of CAS Registry Number 618070-68: (8*6)+(7*1)+(6*8)+(5*0)+(4*7)+(3*0)+(2*6)+(1*8)=151 151 % 10 = 1 So 618070-68-1 is a valid CAS Registry Number.