The CAS Registry Mumber 314280-74-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 3,1,4,2,8 and 0 respectively; the second part has 2 digits, 7 and 4 respectively. Calculate Digit Verification of CAS Registry Number 314280-74: (8*3)+(7*1)+(6*4)+(5*2)+(4*8)+(3*0)+(2*7)+(1*4)=115 115 % 10 = 5 So 314280-74-5 is a valid CAS Registry Number.