实数分类
- 实数按定义分类：
[实数Rleft{egin{array}{l}{有理数Qleft{egin{array}{l}{整数left{egin{array}{l}{正整数N_+}\{零}\{负整数N_-}end{array}
ight}正整数&零Rightarrow 自然数N}\{分数left{egin{array}{l}{正分数}\{负分数}end{array}
ight}有限小数或无限循环小数Rightarrow 小数}end{array}
ight.}\{无理数C_{R}{Q}Leftrightarrow 无限不循环小数Rightarrow 小数}end{array}
ight.
]
- 实数按大小分类：
[实数left{egin{array}{l}{正实数left{egin{array}{l}{正有理数left{egin{array}{l}{正整数}\{正分数}end{array}
ight.}\{正无理数}end{array}
ight.}\{零}\{负实数left{egin{array}{l}{负有理数left{egin{array}{l}{负整数}\{负分数}end{array}
ight.}\{负无理数}end{array}
ight.}end{array}
ight.
]
复数分类
(复数C：z=a+bi(a,bin R)left{egin{array}{l}{实数R:b=0}\{虚数:b eq 0left{egin{array}{l}{纯虚数:a=0}\{混虚数:a eq 0}end{array} ight.}end{array} ight.)