The CAS Registry Mumber 107618-06-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,7,6,1 and 8 respectively; the second part has 2 digits, 0 and 6 respectively. Calculate Digit Verification of CAS Registry Number 107618-06: (8*1)+(7*0)+(6*7)+(5*6)+(4*1)+(3*8)+(2*0)+(1*6)=114 114 % 10 = 4 So 107618-06-4 is a valid CAS Registry Number.