Réponse:
a
[tex]a) \frac{ - 7}{50} + \frac{2}{75} = \frac{ - 7 \times 3}{50 \times 3} + \frac{2 \times 2}{75 \times 2} = \frac{ -21}{150} + \frac{4}{150} = \frac{ - 17}{150} [/tex]
b
[tex]b) \frac{1}{5} + \frac{ - 2}{3} = \frac{1 \times 3}{5 \times 3} + \frac{ - 2 \times 5}{3 \times 5} = \frac{3}{15} + \frac{ - 10}{15} = \frac{ - 7}{15} [/tex]
c
[tex]c) \frac{1}{12} - \frac{1}{9} = \frac{1 \times 3}{12 \times 3} - \frac{1 \times 4}{9 \times 4} = \frac{3}{36} - \frac{4}{36} = \frac{ - 1}{36} [/tex]
d
[tex]d) \frac{4}{18} + \frac{5}{27} = \frac{4 \div 2}{18 \div 2} + \frac{5}{27} = \frac{2 \times 3}{9 \times 3} + \frac{5}{27} = \frac{6 + 5}{27} = \frac{11}{27} [/tex]
