The CAS Registry Mumber 58116-06-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,8,1,1 and 6 respectively; the second part has 2 digits, 0 and 6 respectively. Calculate Digit Verification of CAS Registry Number 58116-06: (7*5)+(6*8)+(5*1)+(4*1)+(3*6)+(2*0)+(1*6)=116 116 % 10 = 6 So 58116-06-6 is a valid CAS Registry Number.