Javascript floating point number addition different outputs
<p>Why this will not give the results as expected?</p>

<pre><code>console.log(0.2+0.1); // gives 0.30000000000000004 
console.log(0.2+0.3); // gives 0.5
console.log(0.2+0.5); // gives 0.7
console.log(0.2+0.4); // gives 0.6000000000000001 
</code></pre>

<p>Why the <code>first</code> and <code>last</code> will not give the results as expected?</p>
