Q:
# What is a non-real number?

**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.

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.

Learn more about Numbers-
Q:
## What is the smallest prime number?

A: The smallest prime number, according to primality as defined by modern mathematicians, is 2. To be prime, a number must be divisible only by itself and 1. ... Full Answer >Filed Under: -
Q:
## What are the common rules when adding significant figures?

A: When adding numbers, the rules of significant figures dictate that the sum should be rounded to the same place as the least significant place of the number... Full Answer >Filed Under: -
Q:
## How many combinations can you make with six digits?

A: Using the digits 0 to 9, with no number repeating itself, 151,200 possible combinations of six digits. However, if a true number is required, meaning 0 can... Full Answer >Filed Under: -
Q:
## What is the last number on Earth?

A: There is no such thing as a last number when it comes to the natural number system. By definition, every number has a number larger than it. Full Answer >Filed Under: