The CAS Registry Mumber 68440-02-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,8,4,4 and 0 respectively; the second part has 2 digits, 0 and 2 respectively. Calculate Digit Verification of CAS Registry Number 68440-02: (7*6)+(6*8)+(5*4)+(4*4)+(3*0)+(2*0)+(1*2)=128 128 % 10 = 8 So 68440-02-8 is a valid CAS Registry Number.