QUESTION : 02

These are simple questions,...
  1...can anyone give the definition for matching..???
  2.... the function of the cascade lines ???

QUESTION : 01

Professor Smith computes the grades as follows : he uses only the first digit ie.9 for 90 etc.... he never had an average of 100..he gives pass to any one who has average above 60 and F to anyone below 60.....the first digit is coded in 8421 code,,,,,,......w,x,y,z may be the inputs..
              Design a circuit using up to two decoders to produce an output 1 iff the student passes........