title: Why decimal.Decimal doesn't support arithmetic operations with float-data type?
body: <p>I am working on some scripts that handle calculation with the need of maintaining high accuracy of the results so I started using decimal.Decimal instead of built-in float. </p>
  
  <p>I know it doesn't work with float-type values and it returns TypeError: unsupported operand type(s) for +: 'decimal.Decimal' and 'float'
  What I need to know exactly is why it doesn't support this type of operations with float. </p>
  
  <p>Sample: </p>
  
  <pre><code>from decimal import Decimal
  
  expr_= 1.2+Decimal('1')
  </code></pre>
  
  <p>As this seems logic for me when I try to add str to float to get this type of error but not while trying to calculate two numeric values. </p>
  
  <p>While I can easily do the same thing using SymPy Float data-type without facing any issues. Ex:</p>
  
  <pre><code>from decimal import Decimal
  from sympy import Float
  expr_=Decimal('1.6')+Float(1.2)
  </code></pre>