kinds of number-like objects into categories called <em>sets</em>:</p>
<ul>
<li>The natural numbers: <span class="inline_math">\( \mathbb{N} = \{0,1,2,3,4,5,6,7, \ldots \, \} \)</span>
</li>
<li>The integers: <span class="inline_math">\( \mathbb{Z} = \{\ldots, -3,-2,-1,0,1,2,3 , \ldots  \, \} \)</span>
</li>
<li>The rational numbers: <span class="inline_math">\( \mathbb{Q} = \{\frac{5}{3}, \frac{22}{7}, 1.5, 0.125,  -7, \, \ldots \, \} \)</span>
</li>
<li>The real numbers: <span class="inline_math">\( \math