The CAS Registry Mumber 103025-40-7 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,3,0,2 and 5 respectively; the second part has 2 digits, 4 and 0 respectively. Calculate Digit Verification of CAS Registry Number 103025-40: (8*1)+(7*0)+(6*3)+(5*0)+(4*2)+(3*5)+(2*4)+(1*0)=57 57 % 10 = 7 So 103025-40-7 is a valid CAS Registry Number.