The CAS Registry Mumber 113850-51-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,3,8,5 and 0 respectively; the second part has 2 digits, 5 and 1 respectively. Calculate Digit Verification of CAS Registry Number 113850-51: (8*1)+(7*1)+(6*3)+(5*8)+(4*5)+(3*0)+(2*5)+(1*1)=104 104 % 10 = 4 So 113850-51-4 is a valid CAS Registry Number.