5.282 Вычислите значение выражения: а) 14-1+ 12; б) 7-3-1; в) 17+3-; г) 23-13-1

1. $$14\frac{9}{13} - 1\frac{5}{13} + 12\frac{11}{13} = 14 - 1 + 12 + \frac{9}{13} - \frac{5}{13} + \frac{11}{13} = 25 + \frac{4}{13} + \frac{11}{13} = 25 + \frac{15}{13} = 25 + 1\frac{2}{13} = 26\frac{2}{13}$$

2. $$7\frac{24}{25} - 3\frac{12}{25} - 1\frac{7}{25} = 7 - 3 - 1 + \frac{24}{25} - \frac{12}{25} - \frac{7}{25} = 3 + \frac{12}{25} - \frac{7}{25} = 3 + \frac{5}{25} = 3\frac{5}{25} = 3\frac{1}{5}$$

3. $$17\frac{7}{40} + 3\frac{9}{40} - \frac{17}{40} = 17 + 3 + \frac{7}{40} + \frac{9}{40} - \frac{17}{40} = 20 + \frac{16}{40} - \frac{17}{40} = 20 - \frac{1}{40} = 19\frac{40}{40} - \frac{1}{40} = 19\frac{39}{40}$$

4. $$23\frac{15}{49} - 13\frac{19}{49} - 1\frac{30}{49} = 22\frac{64}{49} - 13\frac{19}{49} - 1\frac{30}{49} = 22 - 13 - 1 + \frac{64}{49} - \frac{19}{49} - \frac{30}{49} = 8 + \frac{45}{49} - \frac{30}{49} = 8 + \frac{15}{49} = 8\frac{15}{49}$$

Ответ: а) $$26\frac{2}{13}$$; б) $$3\frac{1}{5}$$; в) $$19\frac{39}{40}$$; г) $$8\frac{15}{49}$$.