The CAS Registry Mumber 864409-63-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 8,6,4,4,0 and 9 respectively; the second part has 2 digits, 6 and 3 respectively. Calculate Digit Verification of CAS Registry Number 864409-63: (8*8)+(7*6)+(6*4)+(5*4)+(4*0)+(3*9)+(2*6)+(1*3)=192 192 % 10 = 2 So 864409-63-2 is a valid CAS Registry Number.