The CAS Registry Mumber 340041-02-3 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 3,4,0,0,4 and 1 respectively; the second part has 2 digits, 0 and 2 respectively. Calculate Digit Verification of CAS Registry Number 340041-02: (8*3)+(7*4)+(6*0)+(5*0)+(4*4)+(3*1)+(2*0)+(1*2)=73 73 % 10 = 3 So 340041-02-3 is a valid CAS Registry Number.