\[\boxed{\mathbf{Вариант\ 2.}}\]
\[\boxed{\mathbf{1.}}\]
\[1)\ 0 \cdot 9 = 0\]
\[1 \cdot 20 = 20\]
\[0\ :10 = 0\]
\[30 \cdot 1 = 30\]
\[10 \cdot 0 = 0\]
\[9\ :9 = 1\]
\[15\ :15 = 1\]
\[37 + 0 = 37\]
\[54 - 0 = 54\]
\[2)\ (42 - 20) \cdot 1 = 22 \cdot 1 = 22\]
\[60 \cdot 1 + 39 = 60 + 39 = 99\]
\[\boxed{\mathbf{2.}}\]
\[19 \cdot 1 + 19 > 1 \cdot 19 - 19\]
\[72 \cdot 0 < 72 - 0\]
\[7 \cdot 5 + 7 > 7 \cdot 5 + 5\]
\[4 \cdot 9 < 4 \cdot 9 + 4\]
\[\boxed{\mathbf{3.}}\]
\[3 \cdot 7 + 4 \cdot 6 = 21 + 24 =\]
\[= 45\ (м) - ткани\ \]
\[израсходовали\ всего.\]
\[Ответ:45\ м.\]
\[\boxed{\mathbf{4.}}\]
\[b - b = b \cdot 0\]
\[0 \cdot c < c\ :c\]