1, the easiest way is to right-click on the keyboard of the floating language bar on the desktop to select mathematical symbols, and signs √ and × will appear in the soft keyboard.

2. Hold down the shift key (Alt key) with your left hand, press 4 1420 with your right hand (don't press the one above the keyboard, press the one on the right), release your hand and you will come out. Input 2 15 is x.