Breuken aftrekken (reeks 1)

Trek de breuken af

\(\frac{9}{7}-\frac{9}{10}\)

\(\frac{9}{7}-\frac{9}{10}\\=\frac{90}{70}-\frac{63}{70}\\=\frac{90-63}{70}\\=\frac{27}{70}\)