The CAS Registry Mumber 1243250-04-5 includes 10 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 7 digits, 1,2,4,3,2,5 and 0 respectively; the second part has 2 digits, 0 and 4 respectively. Calculate Digit Verification of CAS Registry Number 1243250-04: (9*1)+(8*2)+(7*4)+(6*3)+(5*2)+(4*5)+(3*0)+(2*0)+(1*4)=105 105 % 10 = 5 So 1243250-04-5 is a valid CAS Registry Number.