reserve fi,psi for Ordinal-Sequence,
  A,A1,B,C,D for Ordinal,
  X,Y for set,
  x,y for object;

theorem Th65:
  A = (A div^ B)*^B+^(A mod^ B)
proof
  (A div^ B)*^B c= A by Th64;
  hence thesis by Def5;
end;
