# 分數

## 分數加減法

${\displaystyle {\frac {1}{3}}+{\frac {1}{4}}}$

${\displaystyle ={\frac {1{\color {red}\times 4}}{3{\color {red}\times 4}}}+{\frac {1{\color {red}\times 3}}{4{\color {red}\times 3}}}}$

${\displaystyle ={\frac {4}{12}}+{\frac {3}{12}}}$

${\displaystyle ={\frac {4+3}{12}}}$

${\displaystyle ={\frac {7}{12}}}$

${\displaystyle {\frac {3}{4}}-{\frac {5}{48}}}$

${\displaystyle ={\frac {3{\color {red}\times 12}}{4{\color {red}\times 12}}}-{\frac {5}{48}}}$

${\displaystyle ={\frac {36}{48}}-{\frac {5}{48}}}$

${\displaystyle ={\frac {36-5}{48}}}$

${\displaystyle ={\frac {31}{48}}}$

## 分子乘除

${\displaystyle {\frac {1}{3}}\times {\frac {1}{4}}}$

${\displaystyle ={\frac {1\times 1}{3\times 4}}}$

${\displaystyle ={\frac {1}{12}}}$

${\displaystyle {\frac {1}{6}}\div {\frac {1}{8}}}$

${\displaystyle ={\frac {1}{6}}\times {\frac {8}{1}}}$

${\displaystyle ={\frac {1\times 8}{6\times 1}}}$

${\displaystyle ={\frac {8/2}{6/2}}}$

${\displaystyle ={\frac {4}{3}}}$

${\displaystyle =1{\frac {1}{3}}}$

## 分數四則運算

• ${\displaystyle (25-{\frac {11}{36}}\times 25)+(11-{\frac {11}{36}}\times 11)}$

${\displaystyle =(25+11)-({\frac {11*25}{36}}+{\frac {11*11}{36}})}$ , (${\displaystyle 25+11=36}$)

${\displaystyle =36-({\frac {11}{36}}(25+11))}$

${\displaystyle =36-11=25}$

• ${\displaystyle {\frac {1}{2-{\frac {11}{18}}}}-{\frac {11}{50}}}$

${\displaystyle ={\frac {1}{\frac {36-11}{18}}}-{\frac {11}{50}}}$

${\displaystyle ={\frac {18}{36-11}}-{\frac {11}{50}}}$ ,(${\displaystyle 36-11=25}$)

${\displaystyle ={\frac {36-11}{50}}={\frac {25}{50}}={\frac {1}{2}}}$