Bài 1: Tính: a) \(\frac{2}{7}\) + \(\frac{4}{7}\) ; \(\frac{6}{7}\) - \(\frac{2}{7}\) ; \(\frac{6}{7
Bài 1: Tính:
a) \(\frac{2}{7}\) + \(\frac{4}{7}\) ; \(\frac{6}{7}\) - \(\frac{2}{7}\) ; \(\frac{6}{7}\) - \(\frac{4}{7}\) ; \(\frac{4}{7}\) + \(\frac{2}{7}\) ;
b) \(\frac{1}{3}\) + \(\frac{5}{12}\) ; \(\frac{9}{12}\) - \(\frac{1}{3}\) ; \(\frac{9}{12}\) - \(\frac{5}{12}\) ; \(\frac{5}{12}\) + \(\frac{1}{3}\).
Lời Giải:
Bài 1:
a) \(\frac{2}{7}\) + \(\frac{4}{7}\) = \(\frac{6}{7}\) ;
\(\frac{6}{7}\) - \(\frac{2}{7}\) = \(\frac{4}{7}\) ;
\(\frac{6}{7}\) - \(\frac{4}{7}\) = \(\frac{2}{7}\) ;
\(\frac{4}{7}\) + \(\frac{2}{7}\) = \(\frac{6}{7}\)
\(\frac{1}{3}\) + \(\frac{5}{12}\) = \(\frac{4}{12}\) + \(\frac{5}{12}\) = \(\frac{9}{12}\) ;
b) \(\frac{9}{12}\) - \(\frac{1}{3}\) = \(\frac{9}{12}\) - \(\frac{4}{12}\) = \(\frac{5}{12}\)
\(\frac{9}{12}\) - \(\frac{5}{12}\) = \(\frac{4}{12}\) ;
\(\frac{5}{12}\) + \(\frac{1}{3}\) = \(\frac{5}{12}\) + \(\frac{4}{12}\) = \(\frac{9}{12}\)