The CAS Registry Mumber 38609-44-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,8,6,0 and 9 respectively; the second part has 2 digits, 4 and 4 respectively. Calculate Digit Verification of CAS Registry Number 38609-44: (7*3)+(6*8)+(5*6)+(4*0)+(3*9)+(2*4)+(1*4)=138 138 % 10 = 8 So 38609-44-8 is a valid CAS Registry Number.