The CAS Registry Mumber 1144516-18-6 includes 10 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 7 digits, 1,1,4,4,5,1 and 6 respectively; the second part has 2 digits, 1 and 8 respectively. Calculate Digit Verification of CAS Registry Number 1144516-18: (9*1)+(8*1)+(7*4)+(6*4)+(5*5)+(4*1)+(3*6)+(2*1)+(1*8)=126 126 % 10 = 6 So 1144516-18-6 is a valid CAS Registry Number.