documentclass[tikz]{standalone}
usepackage{amssymb}
usepackage[backgrounds]{tikz}

makeatletter
deftikz@arc@opt[#1]{% over-write!
  {%
    tikzset{every arc/.try,#1}%
    pgfkeysgetvalue{/tikz/start angle}tikz@s
    pgfkeysgetvalue{/tikz/end angle}tikz@e
    pgfkeysgetvalue{/tikz/delta angle}tikz@d
    ifxtikz@spgfutil@empty%
      pgfmathsetmacrotikz@s{tikz@e-tikz@d}
    else
      ifxtikz@epgfutil@empty%
        pgfmathsetmacrotikz@e{tikz@s+tikz@d}
      fi%
    fi
    tikz@arc@moveto
    xdefpgf@marshal{noexpand%
    tikz@do@arc{tikz@s}{tikz@e}
      {pgfkeysvalueof{/tikz/x radius}}
      {pgfkeysvalueof{/tikz/y radius}}}%
  }%
  pgf@marshal%
  tikz@arcfinal%
}
lettikz@arc@movetorelax
deftikz@arc@movetolineto#1{%
  deftikz@arc@moveto{tikz@@@parse@polar{tikz@arc@@movetolineto#1}(tikz@s:pgfkeysvalueof{/tikz/x radius} and pgfkeysvalueof{/tikz/y radius})}}
deftikz@arc@@movetolineto#1#2{#1{pgfpointadd{#2}{tikz@last@position@saved}}}
tikzset{%
  move to start/.code=tikz@arc@movetolinetopgfpathmoveto,%
  line to start/.code=tikz@arc@movetolinetopgfpathlineto}
makeatother


begin{document}

begin{center}
begin{tikzpicture}[x radius=7cm, y radius=4cm, white, ultra thick]
centering
  draw[fill=blue] (C) arc [line to start, start angle=90, delta angle=-180] -- cycle;
  draw[fill=blue!70] (C) arc [line to start, start angle=90, delta angle=180] -- cycle;
draw[white, fill=blue!55, ultra thick] (-3,0.25) circle [radius=2.75];
draw[white, fill=blue!45, ultra thick] (-2.5,-1) circle [radius=1.75];
node at (1,4.5){huge $mathbb{R}$};
node[white] at (-0.75,2.5){huge $mathbb{Q}$};
node[white] at (3.75,0.25){huge $mathbb{I}$};
node[white] at (-2.25,2){huge $mathbb{Z}$};
node[white] at (-2.25,-0.75){huge $mathbb{N}$};
end{tikzpicture}
end{center}

end{document}