Ответ:
\(72\,090\cdot7=504\,630\); \(2\,160\cdot400=864\,000\); \(68\,240:40=1\,706\); \(238\,800:600=398\); \(694\,703-28\,593=666\,110\); \(71\,346+98\,562=169\,908\).
\(72\,090\cdot7=504\,630\); \(2\,160\cdot400=864\,000\); \(68\,240:40=1\,706\); \(238\,800:600=398\); \(694\,703-28\,593=666\,110\); \(71\,346+98\,562=169\,908\).