The CAS Registry Mumber 140842-89-3 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,4,0,8,4 and 2 respectively; the second part has 2 digits, 8 and 9 respectively. Calculate Digit Verification of CAS Registry Number 140842-89: (8*1)+(7*4)+(6*0)+(5*8)+(4*4)+(3*2)+(2*8)+(1*9)=123 123 % 10 = 3 So 140842-89-3 is a valid CAS Registry Number.