title: How to calculate and store the number in scientific notation?
body: <p>I am using Python to model the statistical physical, so I will deal with small numbers.</p>
  
  <p>For example, </p>
  
  <pre><code>a = 2.22e-300, b = 3e-200
  </code></pre>
  
  <p>and I want to calculate </p>
  
  <pre><code>a * b = 6.66e-500.
  </code></pre>
  
  <p>However, in Python 3 it shows 0.0.</p>
  
  <p>I am thinking to design a data type: the first part to store the float number, which is 6.66 here, and the second part stores the magnitude, which is -500.</p>
  
  <p>May I ask how I can implement this? Or is there any better way to deal with the scientific number?</p>