The CAS Registry Mumber 27245-43-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,7,2,4 and 5 respectively; the second part has 2 digits, 4 and 3 respectively. Calculate Digit Verification of CAS Registry Number 27245-43: (7*2)+(6*7)+(5*2)+(4*4)+(3*5)+(2*4)+(1*3)=108 108 % 10 = 8 So 27245-43-8 is a valid CAS Registry Number.