The CAS Registry Mumber 87379-22-4 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 2 respectively. Calculate Digit Verification of CAS Registry Number 87379-22: (7*8)+(6*7)+(5*3)+(4*7)+(3*9)+(2*2)+(1*2)=174 174 % 10 = 4 So 87379-22-4 is a valid CAS Registry Number.