Let's classify each number:
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√47: This is an irrational number because it cannot be expressed as a fraction of two integers.
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0: This is a rational number because it can be expressed as 0/1. It is also an integer and a whole number.
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0.121212...: This is a repeating decimal, which means it is a rational number. It can be expressed as a fraction: 12/99 = 4/33.
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-9: This is an integer and also a rational number.
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√144: This equals 12, which is a natural number, whole number, and also a rational number.
So, in summary:
- √47: Irrational Number
- 0: Rational Number (also integer, whole number)
- 0.121212...: Rational Number
- -9: Integer (also a rational number)
- √144: Natural Number (also a whole number, rational number)
Therefore, the most specific set to which each number belongs is:
- √47: Irrational Number
- 0: Whole Number (and Integer, Rational Number)
- 0.121212...: Rational Number
- -9: Integer (and Rational Number)
- √144: Natural Number (and Whole Number, Rational Number)