The CAS Registry Mumber 130489-87-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,0,4,8 and 9 respectively; the second part has 2 digits, 8 and 7 respectively. Calculate Digit Verification of CAS Registry Number 130489-87: (8*1)+(7*3)+(6*0)+(5*4)+(4*8)+(3*9)+(2*8)+(1*7)=131 131 % 10 = 1 So 130489-87-1 is a valid CAS Registry Number.