The CAS Registry Mumber 30088-16-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,0,0,8 and 8 respectively; the second part has 2 digits, 1 and 6 respectively. Calculate Digit Verification of CAS Registry Number 30088-16: (7*3)+(6*0)+(5*0)+(4*8)+(3*8)+(2*1)+(1*6)=85 85 % 10 = 5 So 30088-16-5 is a valid CAS Registry Number.