4. Выполните вычитание: 1) 3 1/18 − 1/9; 2) 3 17/27 − 2 13/18; 3) 6 3/8 − 2 5/9; 4) 8 11/42 − 5 43/126; 5) 6 7/45 − 4 7/20; 6) 9 1/21 − 5 16/63.

1. \(3\frac{1}{18}-\frac{1}{9}=3\frac{1}{18}-\frac{2}{18}=2\frac{17}{18}\).
2. \(3\frac{17}{27}-2\frac{13}{18}=3\frac{34}{54}-2\frac{39}{54}=\frac{49}{54}\).
3. \(6\frac{3}{8}-2\frac{5}{9}=6\frac{27}{72}-2\frac{40}{72}=5\frac{59}{72}\).
4. \(8\frac{11}{42}-5\frac{43}{126}=8\frac{33}{126}-5\frac{43}{126}=7\frac{58}{63}\).
5. \(6\frac{7}{45}-4\frac{7}{20}=6\frac{28}{180}-4\frac{63}{180}=5\frac{29}{36}\).
6. \(9\frac{1}{21}-5\frac{16}{63}=9\frac{3}{63}-5\frac{16}{63}=8\frac{50}{63}\).

Ответ: 1) 2 17/18; 2) 49/54; 3) 5 59/72; 4) 7 58/63; 5) 5 29/36; 6) 8 50/63.