The CAS Registry Mumber 5854-13-7 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 5,8,5 and 4 respectively; the second part has 2 digits, 1 and 3 respectively. Calculate Digit Verification of CAS Registry Number 5854-13: (6*5)+(5*8)+(4*5)+(3*4)+(2*1)+(1*3)=107 107 % 10 = 7 So 5854-13-7 is a valid CAS Registry Number.