Respuesta:
le faltan
[tex] \frac{25}{8} [/tex]
Explicación paso a paso:
[tex]3 \frac{1}{8} = \frac{25}{8} [/tex]
[tex] \frac{1}{2} + 5 \frac{3}{4} = \frac{1}{2} + \frac{23}{4} = \frac{4 + 46}{8} = \frac{50}{8} = \frac{25}{4} [/tex]
[tex] \frac{25}{4} - \frac{25}{8} = \frac{200 - 100}{32} = \frac{100}{32} = \frac{25}{8} [/tex]
comprobamos
[tex] \frac{25}{8} + \frac{25}{8} = \frac{200 + 200}{64} = 6 \frac{1}{4 } = \frac{25}{4} [/tex]
Espero sea de ayuda
