The CAS Registry Mumber 38042-51-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,8,0,4 and 2 respectively; the second part has 2 digits, 5 and 1 respectively. Calculate Digit Verification of CAS Registry Number 38042-51: (7*3)+(6*8)+(5*0)+(4*4)+(3*2)+(2*5)+(1*1)=102 102 % 10 = 2 So 38042-51-2 is a valid CAS Registry Number.