7-23 7 =

$$7 - 2\frac{3}{7} = 6\frac{7}{7} - 2\frac{3}{7} = (6-2) + (\frac{7}{7} - \frac{3}{7}) = 4 + \frac{4}{7} = 4\frac{4}{7}$$

Ответ: $$4\frac{4}{7}$$