The CAS Registry Mumber 38819-61-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,8,8,1 and 9 respectively; the second part has 2 digits, 6 and 1 respectively. Calculate Digit Verification of CAS Registry Number 38819-61: (7*3)+(6*8)+(5*8)+(4*1)+(3*9)+(2*6)+(1*1)=153 153 % 10 = 3 So 38819-61-3 is a valid CAS Registry Number.