The CAS Registry Mumber 86758-92-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,6,7,5 and 8 respectively; the second part has 2 digits, 9 and 2 respectively. Calculate Digit Verification of CAS Registry Number 86758-92: (7*8)+(6*6)+(5*7)+(4*5)+(3*8)+(2*9)+(1*2)=191 191 % 10 = 1 So 86758-92-1 is a valid CAS Registry Number.