$\displaystyle 1000 \cdot \left(1- \frac{81}{100} \cdot \frac{4}{100} \right)$\displaystyle 1000 \cdot \left(1- \frac{81}{100} \cdot \frac{4}{100} \right)

$\displaystyle 1000 \cdot \left(1+ \frac{19}{100} \cdot \frac{4}{100} \right)$\displaystyle 1000 \cdot \left(1+ \frac{19}{100} \cdot \frac{4}{100} \right)

$\displaystyle 1000 \cdot \left(1+ \frac{81}{100} \cdot \frac{4}{100} \right)$\displaystyle 1000 \cdot \left(1+ \frac{81}{100} \cdot \frac{4}{100} \right)

$\displaystyle 1000 \cdot \left(1- \frac{19}{100} \cdot \frac{4}{100} \right)$\displaystyle 1000 \cdot \left(1- \frac{19}{100} \cdot \frac{4}{100} \right)