The CAS Registry Mumber 71259-34-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,1,2,5 and 9 respectively; the second part has 2 digits, 3 and 4 respectively. Calculate Digit Verification of CAS Registry Number 71259-34: (7*7)+(6*1)+(5*2)+(4*5)+(3*9)+(2*3)+(1*4)=122 122 % 10 = 2 So 71259-34-2 is a valid CAS Registry Number.