4) 8 5/36 - 1 43/108 ;

4) $$8 \frac{5}{36} - 1 \frac{43}{108} = (8 - 1) + (\frac{5}{36} - \frac{43}{108}) = 7 + (\frac{5 \cdot 3}{36 \cdot 3} - \frac{43}{108}) = 7 + (\frac{15}{108} - \frac{43}{108}) = 7 - \frac{28}{108} = 7 - \frac{7}{27} = 6 \frac{27}{27} - \frac{7}{27} = 6 \frac{20}{27}$$

Ответ: $$6 \frac{20}{27}$$