The CAS Registry Mumber 502483-55-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 5,0,2,4,8 and 3 respectively; the second part has 2 digits, 5 and 5 respectively. Calculate Digit Verification of CAS Registry Number 502483-55: (8*5)+(7*0)+(6*2)+(5*4)+(4*8)+(3*3)+(2*5)+(1*5)=128 128 % 10 = 8 So 502483-55-8 is a valid CAS Registry Number.