The CAS Registry Mumber 349107-02-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 3,4,9,1,0 and 7 respectively; the second part has 2 digits, 0 and 2 respectively. Calculate Digit Verification of CAS Registry Number 349107-02: (8*3)+(7*4)+(6*9)+(5*1)+(4*0)+(3*7)+(2*0)+(1*2)=134 134 % 10 = 4 So 349107-02-4 is a valid CAS Registry Number.