Note: This subject is introduced in the pre‐algebra section (see Chapter
).

The symbol is called a radical sign and is used to designate square root. To designate cube root, a small three is placed above the radical sign, . When two radical signs are next to each other, they automatically mean that the two are multiplied. The multiplication sign may be omitted. Note that the square root of a negative number is not possible within the real number system; a completely different system of imaginary numbers is used. The (so‐called) imaginary numbers are multiples of the imaginary unit i.