\[
\begin{aligned}
7+1&=8,\\
-3+12&=09,\\
187+123&=310,\\
2187+1234&=3421,\\
2187+12345&=14532,\\
2187+123456&=125643,\\
2187+1234567&=1236754,\\
2187+12345678&=12347865,\\
2187+123456789&=123458976,\\
1197+1234567890&=1234569087,\\
-8703+12345678901&=12345670198,\\
-7803+123456789012&=123456781209,\\
2187+1234567890123&=1234567892310,\\
2187+12345678901234&=12345678903421,\\
\end{aligned}
\]

如果我们从 $6+1=7$ 开始

\[
\begin{split}
6+1&=7,\\
-4+12&=08,\\
296+123&=419,\\
286+1234&=1520,\\
286+12345&=12631,\\
286+123456&=123742,\\
286+1234567&=1234853,\\
286+12345678&=12345964,\\
-714+123456789&=123456075,\\
-704+1234567890&=1234567186,\\
-604+12345678901&=12345678297,\\
296+123456789012&=123456789308,\\
296+1234567890123&=1234567890419,\\
286+12345678901234&=12345678901520,\\
\end{split}
\]