1, click insert-> symbol-> other symbols, as shown in the figure;

2. The symbol dialog box pops up, and you can insert symbols as shown in the figure.

Method 2: Take Sogou Pinyin Input Method as an example.

1. Click the right mouse button on the input method soft keyboard to pop up a shortcut menu, and select a mathematical symbol, as shown in the figure;

2. The soft keyboard of mathematical symbols pops up, and you can click the corresponding button with the mouse.