The CAS Registry Mumber 87379-26-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,7,3,7 and 9 respectively; the second part has 2 digits, 2 and 6 respectively. Calculate Digit Verification of CAS Registry Number 87379-26: (7*8)+(6*7)+(5*3)+(4*7)+(3*9)+(2*2)+(1*6)=178 178 % 10 = 8 So 87379-26-8 is a valid CAS Registry Number.