$\begin {array}{lcr}25‰&=&\frac{25}{1000}\\\\&=&\frac{2{,}5}{100}\\\\&=&2{,}5\%\\\\&=&0{,}025\end{array}$

$\begin {array}{lcr}7‰&=&\frac{7}{1000}\\\\&=&\frac{0{,}7}{100}\\\\&=&0{,}7\%\\\\&=&0{,}007\end{array}$

$\begin {array}{lcr}123‰&=&\frac{123}{1000}\\\\&=&\frac{12{,}3}{100}\\\\&=&12{,}3\%\\\\&=&0{,}123\end{array}$

$\begin {array}{lcr}12‰&=&\frac{12}{1000}\\\\&=&\frac{1{,}2}{100}\\\\&=&1{,}2\%\\\\&=&0{,}012\end{array}$

$\begin {array}{lcr}1000‰&=&\frac{1000}{1000}\\\\&=&\frac{100}{100}\\\\&=&100\%\\\\&=&1\end{array}$