Question

9 20 avos - 11 28 avos?

Answer 1

$\frac{9}{20} - \frac{11}{28} = \frac{63-55}{140} = \frac{8}{140} = \frac{2}{35}$

Answer 2

MMC de 20, 28 = 140

$\frac{9}{20} - \frac{11}{28} \\ \\ \frac{63 - 55}{140} \\ \\ \frac{8}{140} \frac{\div}{\div} \frac{4}{4} = \frac{2}{35}$