\[\boxed{Стр.\ \mathbf{73}\text{.\ \ }\mathbf{ОК\ ГДЗ\ - \ домашка\ на\ 5}}\]
\[\boxed{\mathbf{1}.}\]
\[4 \cdot 5 = 20\]
\[6 \cdot 4 = 24\]
\[4 \cdot 7 + 4 = 4 \cdot 8 = 32\]
\[4 \cdot 8 = 32\]
\[4 \cdot 3 + 4 = 4 \cdot 4 = 16\]
\[4 \cdot 4 = 16\]
\[4 \cdot 8 = 32\]
\[4 \cdot 9 - 4 = 4 \cdot 8 = 32\]
\[\boxed{\mathbf{2}.}\]
\[7 \cdot 4 = 28\]
\[4 \cdot 9 = 36\]
\[(13 - 4) \cdot 4 = 9 \cdot 4 = 36\]
\[4 \cdot (11 - 8) = 4 \cdot 3 = 12\]
\[5 \cdot 4 = 20\]
\[4 \cdot 6 = 24\]
\[(17 - 9) \cdot 4 = 8 \cdot 4 = 32\]
\[(50 - 45) \cdot 4 = 5 \cdot 4 = 20\]
\[\boxed{\mathbf{3}.}\]
\[1)\ 4 \cdot 3 = 12\ (пропеллеров) -\]
\[у\ 3\ квадрокоптеров.\]
\[2)\ 4 \cdot 6 = 24\ (пропеллера) -\]
\[у\ 6\ квадрокоптеров.\]
\[3)\ 4 \cdot 8 = 32\ (пропеллера) -\]
\[у\ 8\ квадрокоптеров.\]
\[\boxed{\mathbf{4}.}\]
\[5 \cdot 4 = 20\]
\[2 \cdot 4 = 8\]
\[6 \cdot 4 = 24\]
\[9 \cdot 4 = 36\]
\[7 \cdot 4 = 28\]
\[4 \cdot 4 = 16\]
\[\boxed{\mathbf{5}.}\]
\[28 - 7 = 21\]
\[(13 - 9) \cdot 5 = 20\]
\[8 \cdot 4 = 32\]
\[8\ :4 = 2\]
\[28 + 7 = 35\]
\[(30 - 27) \cdot 4 = 12\]
\[\boxed{\mathbf{6}.}\]
\[60 - 18 = 42\]
\[44 + 26 = 70\]
\[47 + 16 = 63\]
\[54 - 19 = 35\]
\[90 - 25 = 65\]
\[50 + 38 = 88\]
\[100 - 88 = 12\]
\[40 - 26 = 14\]
\[\boxed{\mathbf{7}.}\]
\[4 \cdot 5 = 20\ (см) - периметр\ \]
\[пятиугольника.\]
\[Ответ:20\ см.\]
\[\boxed{\mathbf{Вопрос}.}\]
\[4 \cdot 3 = 12\]
\[4 \cdot 5 = 20\]
\[6 \cdot 4 = 24\]
\[8 \cdot 4 = 32\]
\[4 \cdot 7 = 28\]
\[\boxed{\mathbf{Задание\ на\ полях.\ Цепочка}}\]
\[24\ :4 = 6\]
\[6 \cdot 3 = 18\]
\[18\ :9 = 2\]
\[2 \cdot 8 = 16\]
\[16\ :4 = 4\]