Bài 1: Tính: a) \(\frac{2}{3}\) x \(\frac{4}{7}\) ; \(\frac{8}{21}\) : \(\frac{2}{3}\) ; \(\frac{8}{
Bài 1: Tính:
a) \(\frac{2}{3}\) x \(\frac{4}{7}\) ; \(\frac{8}{21}\) : \(\frac{2}{3}\) ; \(\frac{8}{21}\) : \(\frac{4}{7}\) ; \(\frac{4}{7}\) x \(\frac{2}{3}\)
b) \(\frac{3}{11}\) x 2 ; \(\frac{6}{11}\) : \(\frac{3}{11}\) ; \(\frac{6}{11}\) : 2 ; 2 x \(\frac{3}{11}\) ;
c) 4 x \(\frac{2}{7}\) ; \(\frac{8}{7}\) : \(\frac{2}{7}\) ; \(\frac{8}{7}\) : 4 ; \(\frac{2}{7}\) x 4.
Lời Giải:
Bài 1:
a) \(\frac{2}{3}\) x \(\frac{4}{7}\) = \(\frac{8}{21}\); \(\frac{8}{21}\) : \(\frac{2}{3}\) = \(\frac{8}{21}\) x \(\frac{3}{2}\) = \(\frac{4}{7}\)
\(\frac{8}{21}\) : \(\frac{4}{7}\) = \(\frac{8}{21}\) x \(\frac{7}{4}\) = \(\frac{2}{3}\) ; \(\frac{4}{7}\) x \(\frac{2}{3}\) = \(\frac{8}{21}\)
b) \(\frac{3}{11}\) x 2 = \(\frac{6}{11}\) ; \(\frac{6}{11}\) : \(\frac{3}{11}\) = \(\frac{6}{11}\) × \(\frac{11}{3}\) = 2
\(\frac{6}{11}\) : 2 = \(\frac{6}{11 × 2}\) = \(\frac{3}{11}\) ; 2 x \(\frac{3}{11}\) = \(\frac{2 × 3}{11}\) = \(\frac{6}{11}\)