The CAS Registry Mumber 79759-41-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,9,7,5 and 9 respectively; the second part has 2 digits, 4 and 1 respectively. Calculate Digit Verification of CAS Registry Number 79759-41: (7*7)+(6*9)+(5*7)+(4*5)+(3*9)+(2*4)+(1*1)=194 194 % 10 = 4 So 79759-41-4 is a valid CAS Registry Number.