Réponse :
[tex]A = \frac{13}{25} - \frac{2}{5} \\\\A = \frac{13}{25} - \frac{2*5}{5*5} \\\\A = \frac{13}{25} - \frac{10}{25} \\\\A = \frac{3}{25}[/tex]
[tex]B = \frac{31}{18} - \frac{4}{3} \\\\B = \frac{31}{18} - \frac{4*6}{3*6} \\\\B = \frac{31}{18} - \frac{24}{18}\\\\B = \frac{7}{18}[/tex]
[tex]C = 1 - \frac{5}{42} \\\\C = \frac{42}{42} - \frac{5}{42} \\\\C = \frac{37}{42}[/tex]
j'espère t'avoir aidé !
