The CAS Registry Mumber 129244-68-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,9,2,4 and 4 respectively; the second part has 2 digits, 6 and 8 respectively. Calculate Digit Verification of CAS Registry Number 129244-68: (8*1)+(7*2)+(6*9)+(5*2)+(4*4)+(3*4)+(2*6)+(1*8)=134 134 % 10 = 4 So 129244-68-4 is a valid CAS Registry Number.