Question 406736
<pre><font face = "batangche" color = "indigo" size = 3><b>
I.  Real numbers

    A.  Rational numbers

        1. Integers
           A. Whole numbers
              1. Natural numbers          40
              2. Zero                      0
           B. Negative integers           -3

        2. Common fractions             8.91, {{{2&1/2}}}, {{{-4/11}}}

    B. Irrational numbers
       1.  Algebraic numbers           {{{sqrt(15)}}} 
       2.  Transcendental numbers      1.4545545554...

II.  Imaginary numbers
      
   


-3 is real, rational, negative integer.

 0 is real, rational, integer, whole number, zero.

40 is real, rational, integer, whole number, natural number.

8.91 is real, rational, common fraction (since it's {{{891/100}}}).

{{{sqrt(15)}}} is real, irrational, algebraic.

{{{2&1/2}}} is real, rational, common fraction (since it's {{{5/2}}}).

{{{-4/11}}} is real, rational, common fraction.

1.4545545554... is real, irrational, transcendental.

So the only one that is a natural number is 40.

Edwin</pre>