1. After opening the input method, click the keypad icon of the input method with the right mouse button to pop up a menu.

2. Click "Mathematical Symbol" in the menu with the left mouse button.

3. Click the \ key in the pop-up soft keyboard with the left mouse button.

Method 2: Use word2003 symbol columns.

1. Click the right mouse button in the blank space of word2003 menu bar to pop up the menu.

2. Click "Symbol Bar" in the pop-up menu with the left mouse button.

3. A symbol bar will appear at the bottom of the 3.word2003 interface. Click \ \.