The CAS Registry Mumber 160849-89-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,6,0,8,4 and 9 respectively; the second part has 2 digits, 8 and 9 respectively. Calculate Digit Verification of CAS Registry Number 160849-89: (8*1)+(7*6)+(6*0)+(5*8)+(4*4)+(3*9)+(2*8)+(1*9)=158 158 % 10 = 8 So 160849-89-8 is a valid CAS Registry Number.