The CAS Registry Mumber 14090-18-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,4,0,9 and 0 respectively; the second part has 2 digits, 1 and 8 respectively. Calculate Digit Verification of CAS Registry Number 14090-18: (7*1)+(6*4)+(5*0)+(4*9)+(3*0)+(2*1)+(1*8)=77 77 % 10 = 7 So 14090-18-7 is a valid CAS Registry Number.