The CAS Registry Mumber 56245-03-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,6,2,4 and 5 respectively; the second part has 2 digits, 0 and 3 respectively. Calculate Digit Verification of CAS Registry Number 56245-03: (7*5)+(6*6)+(5*2)+(4*4)+(3*5)+(2*0)+(1*3)=115 115 % 10 = 5 So 56245-03-5 is a valid CAS Registry Number.