user23148: Say I had 1 Bitcoin at the start of the trade yesterday
 @ 01-27 14:29

and the price was 
 USD : 263.95872470902

So, I sold the whole Bitcoin at the average price
Then
 @ 01-29 10:57

I bought back as much Bitcoin as the new price would let me again at the average price of
 USD : 233.55771464647

The price data was taken from crypto-prices.com I just don't see how that could be worked out. I know how to use preev.com to calculate the 'current' value but I don't understand how I would calculate a previous value and work out the difference / or would be, pretend profit.

user5406: 263.95 [USD/BTC] / 233.56 [USD/BTC] * 1 [BTC] = 1.13 [BTC], i.e. for each BTC you sold at the higher price, you can rebuy 1.13 BTC at the lower price.
The underlying concept is explained on Wikipedia: Cross-multiplication.

23148: <p>Say I had 1 Bitcoin at the start of the trade yesterday</p>

<pre><code> @ 01-27 14:29
</code></pre>

<p>and the price was </p>

<pre><code> USD : 263.95872470902
</code></pre>

<p>So, I sold the whole Bitcoin at the average price</p>

<p>Then</p>

<pre><code> @ 01-29 10:57
</code></pre>

<p>I bought back as much Bitcoin as the new price would let me again at the average price of</p>

<pre><code> USD : 233.55771464647
</code></pre>

<p>The price data was taken from crypto-prices.com I just don't see how that could be worked out. I know how to use preev.com to calculate the 'current' value but I don't understand how I would calculate a previous value and work out the difference / or would be, pretend profit.</p>
 5406: <p><code>263.95 [USD/BTC] / 233.56 [USD/BTC] * 1 [BTC] = 1.13 [BTC]</code>, i.e. for each BTC you sold at the higher price, you can rebuy 1.13 BTC at the lower price.</p>

<p>The underlying concept is explained on <a href="http://en.wikipedia.org/wiki/Cross-multiplication" rel="nofollow">Wikipedia: Cross-multiplication</a>.</p>
