The CAS Registry Mumber 107494-89-3 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,7,4,9 and 4 respectively; the second part has 2 digits, 8 and 9 respectively. Calculate Digit Verification of CAS Registry Number 107494-89: (8*1)+(7*0)+(6*7)+(5*4)+(4*9)+(3*4)+(2*8)+(1*9)=143 143 % 10 = 3 So 107494-89-3 is a valid CAS Registry Number.