Brüche

• Grundrechenarten
  • B0:  $a=\dfrac a 1$
  • B1:  $\dfrac a b = \dfrac{ac}{bc}$ (erweitern)
  • B2:  $\dfrac a b\cdot \dfrac c d = \dfrac{ac}{bd}$
  • B3:  $\dfrac a b : \dfrac c d = \dfrac a b\cdot \dfrac d c = \dfrac{ad}{bc}$
  • B4:  $\dfrac a b + \dfrac c d = \dfrac{ad}{bd} + \dfrac{cb}{bd} = \dfrac{ad+cb}{bd}$
  • B5:  $\dfrac a b - \dfrac c d = \dfrac{ad}{bd} - \dfrac{cb}{bd} = \dfrac{ad-cb}{bd}$