The CAS Registry Mumber 94018-42-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,4,0,1 and 8 respectively; the second part has 2 digits, 4 and 2 respectively. Calculate Digit Verification of CAS Registry Number 94018-42: (7*9)+(6*4)+(5*0)+(4*1)+(3*8)+(2*4)+(1*2)=125 125 % 10 = 5 So 94018-42-5 is a valid CAS Registry Number.