減法

減法是一种算術運算，代表从合集中移除对象，可視為「加法的逆運算」。減法的结果称作差。減法是符號是減號（${\displaystyle -}$）。加、減、乘、除合稱四則運算。

${\displaystyle x+y=z}$

${\displaystyle \Rightarrow \ x=z-y}$

${\displaystyle \Rightarrow \ y=z-x}$

5 − 2 = 3

在數式${\displaystyle 5-3=2}$裡，${\displaystyle 5}$稱為被減數，${\displaystyle 3}$稱為減數，${\displaystyle 2}$是${\displaystyle 5}$和${\displaystyle 3}$的差。

减去一个数等于加上这个数的相反数。若果被減數小於減數，得出來的差將會是負數。

${\displaystyle 6-3=3=6+(-3)}$

算术运算

加法 (+) ${\displaystyle \scriptstyle \left.{\begin{matrix}\scriptstyle {\text{项}}\,+\,{\text{项}}\\\scriptstyle {\text{被加数}}\,+\,{\text{被加数}}\\\scriptstyle {\text{addend (broad sense)}}\,+\,{\text{addend (broad sense)}}\\\scriptstyle {\text{augend}}\,+\,{\text{addend (strict sense)}}\end{matrix}}\right\}\,=\,}$ ${\displaystyle \scriptstyle {\text{sum}}}$ 減法 (−) ${\displaystyle \scriptstyle \left.{\begin{matrix}\scriptstyle {\text{项}}\,-\,{\text{项}}\\\scriptstyle {\text{minuend}}\,-\,{\text{subtrahend}}\end{matrix}}\right\}\,=\,}$ ${\displaystyle \scriptstyle {\text{difference}}}$ 乘法 (×) ${\displaystyle \scriptstyle \left.{\begin{matrix}\scriptstyle {\text{factor}}\,\times \,{\text{factor}}\\\scriptstyle {\text{multiplier}}\,\times \,{\text{multiplicand}}\end{matrix}}\right\}\,=\,}$ ${\displaystyle \scriptstyle {\text{product}}}$ 除法 (÷) ${\displaystyle \scriptstyle \left.{\begin{matrix}\scriptstyle {\frac {\scriptstyle {\text{dividend}}}{\scriptstyle {\text{divisor}}}}\\\scriptstyle {\text{ }}\\\scriptstyle {\frac {\scriptstyle {\text{numerator}}}{\scriptstyle {\text{denominator}}}}\end{matrix}}\right\}\,=\,}$ ${\displaystyle {\begin{matrix}\scriptstyle {\text{fraction}}\\\scriptstyle {\text{quotient}}\\\scriptstyle {\text{ratio}}\end{matrix}}}$ 冪 ${\displaystyle \scriptstyle {\text{base}}^{\text{exponent}}\,=\,}$ ${\displaystyle \scriptstyle {\text{power}}}$ n 次方根 (√) ${\displaystyle \scriptstyle {\sqrt[{\text{degree}}]{\scriptstyle {\text{radicand}}}}\,=\,}$ ${\displaystyle \scriptstyle {\text{root}}}$ 对数 (log) ${\displaystyle \scriptstyle \log _{\text{base}}({\text{anti-logarithm}})\,=\,}$ ${\displaystyle \scriptstyle {\text{logarithm}}}$