The CAS Registry Mumber 122600-43-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,2,6,0 and 0 respectively; the second part has 2 digits, 4 and 3 respectively. Calculate Digit Verification of CAS Registry Number 122600-43: (8*1)+(7*2)+(6*2)+(5*6)+(4*0)+(3*0)+(2*4)+(1*3)=75 75 % 10 = 5 So 122600-43-5 is a valid CAS Registry Number.