The CAS Registry Mumber 107165-44-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,7,1,6 and 5 respectively; the second part has 2 digits, 4 and 4 respectively. Calculate Digit Verification of CAS Registry Number 107165-44: (8*1)+(7*0)+(6*7)+(5*1)+(4*6)+(3*5)+(2*4)+(1*4)=106 106 % 10 = 6 So 107165-44-6 is a valid CAS Registry Number.