Question

3/8 MAS 5/7=
3/4 MAS -2/5 MAS -7/10 =
2/5 MAS 7/15 MAS -5/3=

Answer 1

Para poder sumae fracciones primero tenes que encontrar MCM

$\frac{3}{8} + \frac{5}{7} = \frac{3 \times 7 + 5 \times 8}{56} = \frac{21 + 40}{56} = \frac{61}{56}$

-
$\frac{3}{4} + ( - \frac{ 2}{5} ) + ( - \frac{7}{10} ) = \\ \\ \frac{3}{4} - \frac{2}{5} - \frac{7}{10} = \frac{(3 \times 5) - (2 \times 4) - (7 \times 2)}{20} = \frac{15 - 8 - 14}{20} = \frac{15 - 22}{20} = - \frac{7}{20}$

-
$\frac{2}{5} + \frac{7}{15} + ( - \frac{5}{3} ) \\ \\ \frac{2}{5} + \frac{7}{15} - \frac{5}{3} = \frac{(2 \times 3) + 7 - (5 \times 5)}{15} \\ \\ \frac{6 + 7 - 25}{15} = \frac{11 - 25}{15} = \frac{ - 14}{15}$