Réponse :
PS : J'ai passé une demi-heure dessus, pourrais tu me mettre en meilleure réponse (couronne) stp ?
Ex 1 :
[tex]a)\frac{2}{3} + \frac{1}{5} = \frac{10}{15} + \frac{3}{15} = \frac{13}{15}\\\\b)\frac{1}{6} + \frac{4}{18} = \frac{3}{18} + \frac{4}{18} = \frac{7}{18}\\\\c)\frac{1}{4} - \frac{1}{2} = \frac{1}{4} - \frac{2}{4} = -\frac{1}{4}\\\\d)\frac{19}{24} - \frac{2}{12} = \frac{19}{24} - \frac{4}{24} = \frac{15}{24}\\\\e)\frac{-2}{3} - \frac{-3}{4} = \frac{-8}{12} - \frac{-9}{12} = \frac{1}{12}[/tex]
Ex 2 : == --> Bonus
[tex]a)\frac{2}{3} * \frac{1}{5} = \frac{2*1}{3*5} = \frac{2}{15}\\\\b)\frac{9}{8} * \frac{4}{18} = \frac{9*4}{8*18} = \frac{36}{144} == \frac{1}{4}\\\\c)-\frac{5}{4} * \frac{3}{10} = -\frac{5*3}{4*10} = -\frac{15}{40} == \frac{3}{8}\\\\d)\frac{19}{24} * \frac{2}{6} = \frac{19*2}{24*6} = \frac{38}{144} == \frac{19}{72}\\\\e)-\frac{2}{3} * -\frac{3}{4} = \frac{2*3}{3*4} = \frac{6}{12} == \frac{1}{2}\\[/tex]
Ex 3 :
[tex]a)\frac{2}{3} : \frac{1}{5} = \frac{2}{3} * \frac{5}{1} = \frac{2*5}{3*1} = \frac{10}{3}\\\\b)\frac{9}{8} : \frac{4}{18} = \frac{9}{8} * \frac{18}{4} = \frac{9*18}{8*4} = \frac{162}{32} == \frac{81}{16}\\\\c)-\frac{5}{4} : \frac{3}{10} = -\frac{5}{4} * \frac{10}{3} = -\frac{5*10}{4*3} = -\frac{50}{12} == \frac{25}{6}\\\\d)\frac{19}{24} : \frac{2}{6} = \frac{19}{24} * \frac{6}{2} = \frac{19*6}{24*2} = \frac{114}{48} == \frac{19}{8}\\[/tex]
[tex]e) -\frac{2}{3} : -\frac{3}{4} = \frac{2}{3} * \frac{4}{3} = \frac{2*4}{3*3} = \frac{8}{9}[/tex]
