The CAS Registry Mumber 340040-88-2 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 0 respectively; the second part has 2 digits, 8 and 8 respectively. Calculate Digit Verification of CAS Registry Number 340040-88: (8*3)+(7*4)+(6*0)+(5*0)+(4*4)+(3*0)+(2*8)+(1*8)=92 92 % 10 = 2 So 340040-88-2 is a valid CAS Registry Number.