\[\ \boxed{\mathbf{2.}}\]
\[2 \cdot 7 = 14\]
\[7 \cdot 2 = 14\]
\[7 + 7 = 14\]
\[3 \cdot 7 = 21\]
\[7 \cdot 3 = 21\]
\[7 + 7 + 7 = 21\]
\[4 \cdot 7 = 28\]
\[7 \cdot 4 = 28\]
\[7 + 7 + 7 + 7 = 28\]
\[5 \cdot 7 = 35\]
\[7 \cdot 5 = 35\]
\[7 + 7 + 7 + 7 + 7 = 35\]
\[6 \cdot 7 = 42\]
\[7 \cdot 6 = 42\]
\[7 + 7 + 7 + 7 + 7 + 7 = 42\]