The CAS Registry Mumber 25447-70-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,5,4,4 and 7 respectively; the second part has 2 digits, 7 and 0 respectively. Calculate Digit Verification of CAS Registry Number 25447-70: (7*2)+(6*5)+(5*4)+(4*4)+(3*7)+(2*7)+(1*0)=115 115 % 10 = 5 So 25447-70-5 is a valid CAS Registry Number.