Упр.879 ГДЗ Ткачёва 5 класс (Математика)

1) 1 2/7 + x = 2 5/7; 2) x + 4 4/9 = 5 1/9; 3) x — 2 7/31 = 1 30/31;
4) x — 5 3/26 = 2 25/26; 5) 6 2/37 — x = 2 30/37; 6) 4 8/39 — x = 1 31/39.

1) $$1 \frac{2}{7} + x = 2 \frac{5}{7}$$

$$x = 2 \frac{5}{7} — 1 \frac{2}{7} = 1 \frac{3}{7}$$

Проверка:

$$1 \frac{2}{7} + 1 \frac{3}{7} = 2 \frac{5}{7}$$

2) $$x + 4 \frac{4}{9} = 5 \frac{1}{9}$$

$$x = 5 \frac{1}{9} — 4 \frac{4}{9} = 4 \frac{10}{9} — 4 \frac{4}{9} = \frac{6}{9} = \frac{2}{3}$$

Проверка:

$$\frac{2}{3} + 4 \frac{4}{9} = \frac{6}{9} + 4 \frac{4}{9} = 4 \frac{10}{9} = 5 \frac{1}{9}$$

3) $$x — 2 \frac{7}{31} = 1 \frac{30}{31}$$

$$x = 1 \frac{30}{31} + 2 \frac{7}{31} = 3 \frac{37}{31} = 4 \frac{6}{31}$$

Проверка:

$$4 \frac{6}{31} — 2 \frac{7}{31} = 3 \frac{37}{31} — 2 \frac{7}{31} = 1 \frac{30}{31}$$

4) $$x — 5 \frac{3}{26} = 2 \frac{25}{26}$$

$$x = 2 \frac{25}{26} + 5 \frac{3}{26} = 7 \frac{28}{26} = 8 \frac{2}{26} = 8 \frac{1}{13}$$

Проверка:

$$8 \frac{1}{13} — 5 \frac{3}{26} = 8 \frac{2}{26} — 5 \frac{3}{26} = 7 \frac{28}{26} — 5 \frac{3}{26} = 2 \frac{25}{26}$$

5) $$6 \frac{2}{37} — x = 2 \frac{30}{37}$$

$$x = 6 \frac{2}{37} — 2 \frac{30}{37} = 5 \frac{39}{37} — 2 \frac{30}{37} = 3 \frac{9}{37}$$

Проверка:

$$6 \frac{2}{37} — 3 \frac{9}{37} = 5 \frac{39}{37} — 3 \frac{9}{37} = 2 \frac{30}{37}$$

6) $$4 \frac{8}{39} — x = 1 \frac{31}{39}$$

$$x = 4 \frac{8}{39} — 1 \frac{31}{39} = 3 \frac{47}{39} — 1 \frac{31}{39} = 2 \frac{16}{39}$$

Проверка:

$$4 \frac{8}{39} — 2 \frac{16}{39} = 3 \frac{47}{39} — 2 \frac{16}{39} = 1 \frac{31}{39}$$

Ответ

1) $$1 \frac{3}{7}$$; 2) $$\frac{2}{3}$$; 3) $$4 \frac{6}{31}$$; 4) $$8 \frac{1}{13}$$; 5) $$3 \frac{9}{37}$$; 6) $$2 \frac{16}{39}$$.