(7- 3 8/9 - 3/7) : 3 1/9 - 4 5/7= По действиям! Прошу, помогите!

$(7-3\frac{8}{9}-\frac{3}{7}):3\frac{1}{9}-4\frac{5}{7} = \\\\1) 7-3\frac{8}{9} = 3\frac{1}{9}\\\\2) 3\frac{1}{9} - \frac{3}{7} = 3\frac{7}{63} - \frac{27}{63} = 2\frac{70}{63} - \frac{27}{63} = 2\frac{43}{63}\\\\3) 2\frac{43}{63} : 3\frac{1}{9} = \frac{169}{63} : \frac{28}{9} = \frac{169*9}{63*28} = \frac{169}{7*28} = \frac{169}{196}$

$4) \frac{169}{196} - 4\frac{5}{7} = \frac{169}{196} - 4\frac{140}{196} = -(4\frac{140}{196} - \frac{169}{196}) = -(3\frac{336}{196} - \frac{169}{196}) = -3\frac{167}{196}$

Ответ: $-3\frac{167}{196}$