The CAS Registry Mumber 104477-48-7 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,4,4,7 and 7 respectively; the second part has 2 digits, 4 and 8 respectively. Calculate Digit Verification of CAS Registry Number 104477-48: (8*1)+(7*0)+(6*4)+(5*4)+(4*7)+(3*7)+(2*4)+(1*8)=117 117 % 10 = 7 So 104477-48-7 is a valid CAS Registry Number.