ВАРИАНТ 3. 1. Выполните действие: а) 4,6-(-2,5); б) -25,344 : (-3,6); в) -1 \(\frac{1}{7}\) \(\cdot\) \(\frac{5}{16}\); г) 1 \(\frac{1}{8}\) : \(-3 \frac{3}{8}\).

Решение:

а) 4,6-(-2,5)

4,6 - (-2,5) = 4,6 + 2,5 = 7,1

б) -25,344 : (-3,6)

-25,344 : (-3,6) = 25,344 : 3,6 = 253,44 : 36 = 7,04

в) -1 \(\frac{1}{7}\) \(\cdot\) \(\frac{5}{16}\)

-1 \(\frac{1}{7}\) \(\cdot\) \(\frac{5}{16}\) = -\(\frac{8}{7}\) \(\cdot\) \(\frac{5}{16}\) = -\(\frac{8 \cdot 5}{7 \cdot 16}\) = -\(\frac{40}{112}\) = -\(\frac{5}{14}\)

г) 1 \(\frac{1}{8}\) : \(-3 \frac{3}{8}\)

1 \(\frac{1}{8}\) : \(-3 \frac{3}{8}\) = \(\frac{9}{8}\) : \(-\frac{27}{8}\) = \(\frac{9}{8}\) \(\cdot\) \(-\frac{8}{27}\) = -\(\frac{9 \cdot 8}{8 \cdot 27}\) = -\(\frac{72}{216}\) = -\(\frac{1}{3}\)

Ответ: а) 7,1; б) 7,04; в) -\( \frac{5}{14} \); г) -\( \frac{1}{3} \).