The CAS Registry Mumber 25078-75-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,5,0,7 and 8 respectively; the second part has 2 digits, 7 and 5 respectively. Calculate Digit Verification of CAS Registry Number 25078-75: (7*2)+(6*5)+(5*0)+(4*7)+(3*8)+(2*7)+(1*5)=115 115 % 10 = 5 So 25078-75-5 is a valid CAS Registry Number.