reserve a,b,p,k,l,m,n,s,h,i,j,t,i1,i2 for natural Number;

theorem
  k <> 0 implies (k * n) div k = n
proof
A0: k is Nat & n is Nat by TARSKI:1;
  assume
A1: k <> 0;
  k * n = k * n + 0;
  hence thesis by A0,A1,Def1;
end;
