To insert a square root (a radical), you can click on the "√" button next to "A B C" on the Desmos keyboard. You can also type "sqrt" in the expression line, which will automatically convert into √
To enter the cubed root symbol from the Desmos keyboard, click on FUNCTIONS and then Misc.
Looking for radicals with an index greater than 3? Try using our shortcut by typing nthroot into the expression list.