Q:

# What is a non-real number?

A:

A non-real, or imaginary, number is any number that, when multiplied by itself, produces a negative number. Mathematicians use the letter "i" to symbolize the square root of -1. An imaginary number is any real number multiplied by i. For example, 5i is imaginary; the square of 5i is -25.

## Keep Learning

Credit: Toby Burrows Digital Vision Getty Images

No real negative number can have a negative square root, because even a negative number multiplied by itself produces a positive product. Real numbers are those numbers that represent a quantity along a number line, including all positive and negative numbers and zero. Irrational numbers, even though they cannot be expressed as a precise fraction or decimal, are considered real numbers because they do exist at some place on the number line, even if that place is not precisely defined.

Sources:

## Related Questions

• A: A nonzero number is any number that is not equal to zero. This includes both positive and negative numbers as well as fractions and irrational numbers.... Full Answer >
Filed Under:
• A: A number model in math is a sentence that illustrates how the parts of a number story are related. The equation may include addition, subtraction, division... Full Answer >
Filed Under:
• A: Leonardo Pisano, who is better known by the name Fibonacci, introduced the Hindu-Arabic number system to Europe at the beginning of the 13th century throug... Full Answer >
Filed Under:
• A: Twenty-nine is a prime number, as its only divisors are 1 and 29. A prime number is defined as a whole number that is greater than 1 and is not evenly divi... Full Answer >
Filed Under:
PEOPLE SEARCH FOR