The CAS Registry Mumber 91875-16-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,1,8,7 and 5 respectively; the second part has 2 digits, 1 and 6 respectively. Calculate Digit Verification of CAS Registry Number 91875-16: (7*9)+(6*1)+(5*8)+(4*7)+(3*5)+(2*1)+(1*6)=160 160 % 10 = 0 So 91875-16-0 is a valid CAS Registry Number.