title: Methods of BigDecimal to go down scale and precision
body: <p>I need a method that go down the scale of a BigDecimal number created as variable</p>
  
  <p>Example:</p>
  
  <pre><code>number1 = BigDecimal.new('154.4978')
  number1 =&gt; 154.4978
  </code></pre>
  
  <p>now I want that number1 = 154.49. How I go down the scale?</p>