Ответ:
\(420 : 7 = 60\).
\(60 - 50 = 10\).
\(10 : 70 = \frac{1}{7}\).
\(\frac{1}{7} \cdot 6 = \frac{6}{7}\).
Ответ: \(\frac{6}{7}\).
\(420 : 7 = 60\).
\(60 - 50 = 10\).
\(10 : 70 = \frac{1}{7}\).
\(\frac{1}{7} \cdot 6 = \frac{6}{7}\).
Ответ: \(\frac{6}{7}\).