The 2 in the upper right corner of the number is generally called superscript or square. Both the input method and computer characters on the mobile phone can be typed. I take the mobile phone as an example and actually operate it again.

The first step is to use the input method that comes with the mobile phone or download an input method. Generally, the downloaded input method is better than the system. I use sogou input method. As shown in the figure below:

Step 2: If the input method is downloaded by yourself, you need to set it yourself. Click the "Settings" button on the mobile phone to change the default input method of the system to the input method downloaded by yourself. As shown in the figure below:

Step 3, enter the number you need to enter in the input dialog box, then click the "symbol" button in the lower left corner, select the "Mathematics" column and drop it down. See a small number "2" and click to complete the operation! As shown in the figure below: