The CAS Registry Mumber 123047-55-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,3,0,4 and 7 respectively; the second part has 2 digits, 5 and 5 respectively. Calculate Digit Verification of CAS Registry Number 123047-55: (8*1)+(7*2)+(6*3)+(5*0)+(4*4)+(3*7)+(2*5)+(1*5)=92 92 % 10 = 2 So 123047-55-2 is a valid CAS Registry Number.