The CAS Registry Mumber 107174-04-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,7,1,7 and 4 respectively; the second part has 2 digits, 0 and 4 respectively. Calculate Digit Verification of CAS Registry Number 107174-04: (8*1)+(7*0)+(6*7)+(5*1)+(4*7)+(3*4)+(2*0)+(1*4)=99 99 % 10 = 9 So 107174-04-9 is a valid CAS Registry Number.