<p>I'm trying to create a Crystal Reports formula field (to calculate the percentage change in a price) that will return "N/A" if a particular report field is null, but return a number to two decimal places using accounting format (negative numbers surrounded by parentheses) if it is not.</p>

<p>The closest I have been able to manage is this:</p>

<pre><code>If IsNull({ValuationReport.YestPrice}) Then
    'N/A'
Else
    ToText({@Price}/{ValuationReport.YestPrice}*100-100, '###.00', 2)
</code></pre>

<p>However this represents negative numbers using a negative sign, not parentheses. </p>

<p>I tried format strings like '###.00;(###.00)' and '(###.00)' but these were rejected as invalid. How can I achieve my goal?</p>

I think you are looking for
```
ToText(CCur(@Price}/{ValuationReport.YestPrice}*100-100))
```
You can use
```
CCur
```
to convert numbers or string to Curency formats.
```
CCur(number)
```
or
```
CCur(string)
```
I think this may be what you are looking for,
```
Replace (ToText(CCur({field})),"$" , "")
```
that will give the parentheses for negative numbers
It is a little hacky, but I'm not sure CR is very kind in the ways of formatting