The CAS Registry Mumber 1403983-89-0 includes 10 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 7 digits, 1,4,0,3,9,8 and 3 respectively; the second part has 2 digits, 8 and 9 respectively. Calculate Digit Verification of CAS Registry Number 1403983-89: (9*1)+(8*4)+(7*0)+(6*3)+(5*9)+(4*8)+(3*3)+(2*8)+(1*9)=170 170 % 10 = 0 So 1403983-89-0 is a valid CAS Registry Number.