\[\mathbf{Страница\ 51.}\]
\[\boxed{\mathbf{4.}}\]
\[1)\ 14,\ 21,\ 28,\ 35,\ 42,\ 49.\]
\[2)\ 4,\ 6,\ 8,\ 10,\ 12,\ 14,\ 16,\ 18,\ 20,\ \]
\[22,\ 24,\ 26,\ 28.\]
\[3)\ 20,\ 30,\ 40,\ 50,\ 60,\ 70.\]
\[4)\ 22,\ 24,\ 26,\ 28,\ 32,\ 34,\ 36,\ 38,\ \ \]
\[40,\ 42,\ 44,\ 46,\ 48.\]
\[\boxed{\mathbf{5.}}\]
\[\textbf{а)}\]
\[\textbf{б)}\ \]
\[\boxed{\mathbf{6.}}\]
\[\textbf{а)}\ 37\]
\[\textbf{б)}\ 865\]
\[\textbf{в)}\ 8975\]
\[\textbf{г)}\ 77\ 898\]
\[\textbf{д)}\ 75\]
\[\textbf{е)}\ 415\]
\[\textbf{ж)}\ 6198\]
\[\textbf{з)}\ 83\ 834\]
\[\textbf{и)}\ 46\ 302\]
\[к)\ 1232\]
\[л)\ 122\ 302\]
\[м)\ 70\ 544\]
\[\boxed{\mathbf{7.}}\]
\[54\ :6 + 35\ :7 = 9 + 5 = 14\ (Н)\]
\[84\ :2 - 17 = 42 - 17 = 25\ (Р)\]
\[(36 + 24) \cdot 2\ :30 = 120\ :30 =\]
\[= 4\ (П)\]
\[330\ :(57 - 9 \cdot 3) = 330\ :30 =\]
\[= 11\ (С)\]
\[(16 + 33)\ :(25 - 18) = 49\ :7 =\]
\[= 7\ (И)\]
\[18 \cdot 3 - 16 \cdot 3 = 54 - 48 = 6\ (О)\]
\[15 \cdot 3\ :5 = 45\ :5 = 9\ (Т)\]
\[820\ :20 - 2 = 41 - 2 = 39\ (А)\]
\[Зашифрованное\ слово:\]
\[ТРАНСПОРТИР - инструмент\ \ \]
\[для\ измерения\ углов.\]