Question 48107
1/5 = A real number.*  A rational number because it can be written as a ratio (1:5), a fraction (1/5) or a terminating or repeating decimal (.20)**
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1/4 = A real number. A rational number because 1/4 or 1:4 or .25 (a terminating or ending decimal)
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1/9 = A real number.  A rational number because 1/9 or 1:9 or .1111 (a repeating decimal)
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{{{(pi)}}} = A real number.  An irrational number because {{{(pi)}}} cannot be written as a fraction, ratio or a terminating or repeating decimal.  {{{(pi)}}} = 3.141592654 and on and on and on.
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i2 = An unreal number because the square root of a negative number does not exist in the real number system.  A complex number because "i" stands for imaginary number and it can be written as 0+i2 which is the standard from of a complex number.  
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* Real numbers can be written on the number line.
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** The definition of a rational number is a number that can be written either as a fraction, a ratio or a number in which the decimal form either terminates or keeps repeating.
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Example: 1/2 = .50 (the decimal terminates)
Example: 2/3 = 2:3 = .666 (the decimal just keeps going in a repeating fashion).