The CAS Registry Mumber 38519-25-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,8,5,1 and 9 respectively; the second part has 2 digits, 2 and 5 respectively. Calculate Digit Verification of CAS Registry Number 38519-25: (7*3)+(6*8)+(5*5)+(4*1)+(3*9)+(2*2)+(1*5)=134 134 % 10 = 4 So 38519-25-4 is a valid CAS Registry Number.