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# What is a non-real number?

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### Quick Answer

**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.

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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.

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Q:
## What is a non-integer number?

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Full Answer >**Non-integers include fractions, decimal numbers and imaginary numbers.**In math, integers include the set of all the counting numbers, their inverses or negatives, and zero, leaving all other numbers as non-integers. There are an infinite number of non-integers, just as there is an infinite number of integers.Filed Under: -
Q:
## Is pi a real number?

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Full Answer >**Pi is a real number, as all numbers that exist on a number line are real.**Real numbers include all rational and irrational numbers; pi is defined as an irrational number.Filed Under: -
Q:
## What is the real number that corresponds to a point on a line?

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Full Answer >**Every point on a number line corresponds to a unique real number.**A line is an infinite set of points and the set of real numbers is also infinite. Thus, there exists a one-to-one correspondence between the set of real numbers and the points on a number line.Filed Under: -
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## What is a negative minus a negative?

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Full Answer >**A negative minus a negative is equal to another negative number, a positive number or zero, depending upon the numbers in the equation.**Subtracting a negative number from another negative number is the same thing as adding a positive number.Filed Under: